diff --git a/_arrayEach.js b/_arrayEach.js
index 0158205ee..5c7b057ec 100644
--- a/_arrayEach.js
+++ b/_arrayEach.js
@@ -1,6 +1,5 @@
 /**
- * A specialized version of `_.forEach` for arrays without support for
- * iteratee shorthands.
+ * A specialized version of `_.forEach` for arrays.
  *
  * @private
  * @param {Array} [array] The array to iterate over.
diff --git a/_arrayEachRight.js b/_arrayEachRight.js
index 713406c15..fa885a744 100644
--- a/_arrayEachRight.js
+++ b/_arrayEachRight.js
@@ -1,6 +1,5 @@
 /**
- * A specialized version of `_.forEachRight` for arrays without support for
- * iteratee shorthands.
+ * A specialized version of `_.forEachRight` for arrays.
  *
  * @private
  * @param {Array} [array] The array to iterate over.
diff --git a/_arrayEvery.js b/_arrayEvery.js
index a24e76600..aa2462269 100644
--- a/_arrayEvery.js
+++ b/_arrayEvery.js
@@ -1,6 +1,5 @@
 /**
- * A specialized version of `_.every` for arrays without support for
- * iteratee shorthands.
+ * A specialized version of `_.every` for arrays.
  *
  * @private
  * @param {Array} [array] The array to iterate over.
diff --git a/_arrayFilter.js b/_arrayFilter.js
index 84b6e7e28..4a586f375 100644
--- a/_arrayFilter.js
+++ b/_arrayFilter.js
@@ -1,6 +1,5 @@
 /**
- * A specialized version of `_.filter` for arrays without support for
- * iteratee shorthands.
+ * A specialized version of `_.filter` for arrays.
  *
  * @private
  * @param {Array} [array] The array to iterate over.
diff --git a/_arrayMap.js b/_arrayMap.js
index 811f9dbb3..9f29ecb79 100644
--- a/_arrayMap.js
+++ b/_arrayMap.js
@@ -1,6 +1,5 @@
 /**
- * A specialized version of `_.map` for arrays without support for iteratee
- * shorthands.
+ * A specialized version of `_.map` for arrays.
  *
  * @private
  * @param {Array} [array] The array to iterate over.
diff --git a/_arrayReduce.js b/_arrayReduce.js
index 15a961582..f14a02e90 100644
--- a/_arrayReduce.js
+++ b/_arrayReduce.js
@@ -1,6 +1,5 @@
 /**
- * A specialized version of `_.reduce` for arrays without support for
- * iteratee shorthands.
+ * A specialized version of `_.reduce` for arrays.
  *
  * @private
  * @param {Array} [array] The array to iterate over.
diff --git a/_arrayReduceRight.js b/_arrayReduceRight.js
index 63d2ca542..bd49f47bc 100644
--- a/_arrayReduceRight.js
+++ b/_arrayReduceRight.js
@@ -1,6 +1,5 @@
 /**
- * A specialized version of `_.reduceRight` for arrays without support for
- * iteratee shorthands.
+ * A specialized version of `_.reduceRight` for arrays.
  *
  * @private
  * @param {Array} [array] The array to iterate over.
diff --git a/_arraySome.js b/_arraySome.js
index afffba804..73be88a5e 100644
--- a/_arraySome.js
+++ b/_arraySome.js
@@ -1,6 +1,5 @@
 /**
- * A specialized version of `_.some` for arrays without support for iteratee
- * shorthands.
+ * A specialized version of `_.some` for arrays.
  *
  * @private
  * @param {Array} [array] The array to iterate over.
diff --git a/_baseDifference.js b/_baseDifference.js
index be119496a..f1bda043c 100644
--- a/_baseDifference.js
+++ b/_baseDifference.js
@@ -9,7 +9,7 @@ const LARGE_ARRAY_SIZE = 200;
 
 /**
  * The base implementation of methods like `_.difference` without support
- * for excluding multiple arrays or iteratee shorthands.
+ * for excluding multiple arrays.
  *
  * @private
  * @param {Array} array The array to inspect.
diff --git a/_baseEach.js b/_baseEach.js
index 1495f8376..f7ab97790 100644
--- a/_baseEach.js
+++ b/_baseEach.js
@@ -2,7 +2,7 @@ import baseForOwn from './_baseForOwn.js';
 import createBaseEach from './_createBaseEach.js';
 
 /**
- * The base implementation of `_.forEach` without support for iteratee shorthands.
+ * The base implementation of `_.forEach`.
  *
  * @private
  * @param {Array|Object} collection The collection to iterate over.
diff --git a/_baseEachRight.js b/_baseEachRight.js
index c722b0557..a4112929d 100644
--- a/_baseEachRight.js
+++ b/_baseEachRight.js
@@ -2,7 +2,7 @@ import baseForOwnRight from './_baseForOwnRight.js';
 import createBaseEach from './_createBaseEach.js';
 
 /**
- * The base implementation of `_.forEachRight` without support for iteratee shorthands.
+ * The base implementation of `_.forEachRight`.
  *
  * @private
  * @param {Array|Object} collection The collection to iterate over.
diff --git a/_baseEvery.js b/_baseEvery.js
index 96964b9d5..f417be0c7 100644
--- a/_baseEvery.js
+++ b/_baseEvery.js
@@ -1,7 +1,7 @@
 import baseEach from './_baseEach.js';
 
 /**
- * The base implementation of `_.every` without support for iteratee shorthands.
+ * The base implementation of `_.every`.
  *
  * @private
  * @param {Array|Object} collection The collection to iterate over.
diff --git a/_baseFilter.js b/_baseFilter.js
index 4376c7908..7c282c082 100644
--- a/_baseFilter.js
+++ b/_baseFilter.js
@@ -1,7 +1,7 @@
 import baseEach from './_baseEach.js';
 
 /**
- * The base implementation of `_.filter` without support for iteratee shorthands.
+ * The base implementation of `_.filter`.
  *
  * @private
  * @param {Array|Object} collection The collection to iterate over.
diff --git a/_baseFindIndex.js b/_baseFindIndex.js
index 26042d78e..a5e810a22 100644
--- a/_baseFindIndex.js
+++ b/_baseFindIndex.js
@@ -1,6 +1,5 @@
 /**
- * The base implementation of `_.findIndex` and `_.findLastIndex` without
- * support for iteratee shorthands.
+ * The base implementation of `_.findIndex` and `_.findLastIndex`.
  *
  * @private
  * @param {Array} array The array to inspect.
diff --git a/_baseFindKey.js b/_baseFindKey.js
index d840ed875..c4ebfb084 100644
--- a/_baseFindKey.js
+++ b/_baseFindKey.js
@@ -1,7 +1,6 @@
 /**
- * The base implementation of methods like `_.findKey` and `_.findLastKey`,
- * without support for iteratee shorthands, which iterates over `collection`
- * using `eachFunc`.
+ * The base implementation of methods like `_.findKey` and `_.findLastKey`
+ * which iterates over `collection` using `eachFunc`.
  *
  * @private
  * @param {Array|Object} collection The collection to inspect.
diff --git a/_baseForOwn.js b/_baseForOwn.js
index 2293e9a6c..e560a9b76 100644
--- a/_baseForOwn.js
+++ b/_baseForOwn.js
@@ -2,7 +2,7 @@ import baseFor from './_baseFor.js';
 import keys from './keys.js';
 
 /**
- * The base implementation of `_.forOwn` without support for iteratee shorthands.
+ * The base implementation of `_.forOwn`.
  *
  * @private
  * @param {Object} object The object to iterate over.
diff --git a/_baseForOwnRight.js b/_baseForOwnRight.js
index 06871b4bb..c44d69e56 100644
--- a/_baseForOwnRight.js
+++ b/_baseForOwnRight.js
@@ -2,7 +2,7 @@ import baseForRight from './_baseForRight.js';
 import keys from './keys.js';
 
 /**
- * The base implementation of `_.forOwnRight` without support for iteratee shorthands.
+ * The base implementation of `_.forOwnRight`.
  *
  * @private
  * @param {Object} object The object to iterate over.
diff --git a/_baseIntersection.js b/_baseIntersection.js
index 7935b4d99..3fb8f0af3 100644
--- a/_baseIntersection.js
+++ b/_baseIntersection.js
@@ -8,8 +8,8 @@ import cacheHas from './_cacheHas.js';
 const nativeMin = Math.min;
 
 /**
- * The base implementation of methods like `_.intersection`, without support
- * for iteratee shorthands, that accepts an array of arrays to inspect.
+ * The base implementation of methods like `_.intersection` that accepts an
+ * array of arrays to inspect.
  *
  * @private
  * @param {Array} arrays The arrays to inspect.
diff --git a/_baseIsMatch.js b/_baseIsMatch.js
index 5dc19d211..c70054185 100644
--- a/_baseIsMatch.js
+++ b/_baseIsMatch.js
@@ -6,7 +6,7 @@ const COMPARE_PARTIAL_FLAG = 1;
 const COMPARE_UNORDERED_FLAG = 2;
 
 /**
- * The base implementation of `_.isMatch` without support for iteratee shorthands.
+ * The base implementation of `_.isMatch`.
  *
  * @private
  * @param {Object} object The object to inspect.
diff --git a/_baseIteratee.js b/_baseIteratee.js
deleted file mode 100644
index af052002e..000000000
--- a/_baseIteratee.js
+++ /dev/null
@@ -1,31 +0,0 @@
-import baseMatches from './_baseMatches.js';
-import baseMatchesProperty from './_baseMatchesProperty.js';
-import identity from './identity.js';
-import isArray from './isArray.js';
-import property from './property.js';
-
-/**
- * The base implementation of `_.iteratee`.
- *
- * @private
- * @param {*} [value=_.identity] The value to convert to an iteratee.
- * @returns {Function} Returns the iteratee.
- */
-function baseIteratee(value) {
-  // Don't store the `typeof` result in a variable to avoid a JIT bug in Safari 9.
-  // See https://bugs.webkit.org/show_bug.cgi?id=156034 for more details.
-  if (typeof value == 'function') {
-    return value;
-  }
-  if (value == null) {
-    return identity;
-  }
-  if (typeof value == 'object') {
-    return isArray(value)
-      ? baseMatchesProperty(value[0], value[1])
-      : baseMatches(value);
-  }
-  return property(value);
-}
-
-export default baseIteratee;
diff --git a/_baseMap.js b/_baseMap.js
index 0cc1933b1..3e9b16d0e 100644
--- a/_baseMap.js
+++ b/_baseMap.js
@@ -2,7 +2,7 @@ import baseEach from './_baseEach.js';
 import isArrayLike from './isArrayLike.js';
 
 /**
- * The base implementation of `_.map` without support for iteratee shorthands.
+ * The base implementation of `_.map`.
  *
  * @private
  * @param {Array|Object} collection The collection to iterate over.
diff --git a/_baseMean.js b/_baseMean.js
deleted file mode 100644
index c87baec2c..000000000
--- a/_baseMean.js
+++ /dev/null
@@ -1,20 +0,0 @@
-import baseSum from './_baseSum.js';
-
-/** Used as references for various `Number` constants. */
-const NAN = 0 / 0;
-
-/**
- * The base implementation of `_.mean` and `_.meanBy` without support for
- * iteratee shorthands.
- *
- * @private
- * @param {Array} array The array to iterate over.
- * @param {Function} iteratee The function invoked per iteration.
- * @returns {number} Returns the mean.
- */
-function baseMean(array, iteratee) {
-  const length = array == null ? 0 : array.length;
-  return length ? (baseSum(array, iteratee) / length) : NAN;
-}
-
-export default baseMean;
diff --git a/_baseOrderBy.js b/_baseOrderBy.js
index 147612a82..a45eac894 100644
--- a/_baseOrderBy.js
+++ b/_baseOrderBy.js
@@ -1,5 +1,4 @@
 import arrayMap from './_arrayMap.js';
-import baseIteratee from './_baseIteratee.js';
 import baseMap from './_baseMap.js';
 import baseSortBy from './_baseSortBy.js';
 import compareMultiple from './_compareMultiple.js';
@@ -16,7 +15,7 @@ import identity from './identity.js';
  */
 function baseOrderBy(collection, iteratees, orders) {
   let index = -1;
-  iteratees = arrayMap(iteratees.length ? iteratees : [identity], value => baseIteratee(value));
+  iteratees = iteratees.length ? iteratees : [identity];
 
   const result = baseMap(collection, (value, key, collection) => {
     const criteria = arrayMap(iteratees, iteratee => iteratee(value));
diff --git a/_basePickBy.js b/_basePickBy.js
index 67d04cb87..e2cafb0c8 100644
--- a/_basePickBy.js
+++ b/_basePickBy.js
@@ -3,7 +3,7 @@ import baseSet from './_baseSet.js';
 import castPath from './_castPath.js';
 
 /**
- * The base implementation of  `_.pickBy` without support for iteratee shorthands.
+ * The base implementation of  `_.pickBy`.
  *
  * @private
  * @param {Object} object The source object.
diff --git a/_basePullAll.js b/_basePullAll.js
index 19784a9c1..57dd0c3a7 100644
--- a/_basePullAll.js
+++ b/_basePullAll.js
@@ -10,8 +10,7 @@ const arrayProto = Array.prototype;
 const splice = arrayProto.splice;
 
 /**
- * The base implementation of `_.pullAllBy` without support for iteratee
- * shorthands.
+ * The base implementation of `_.pullAllBy`.
  *
  * @private
  * @param {Array} array The array to modify.
diff --git a/_baseReduce.js b/_baseReduce.js
index e836d73a4..1d559b719 100644
--- a/_baseReduce.js
+++ b/_baseReduce.js
@@ -1,6 +1,6 @@
 /**
- * The base implementation of `_.reduce` and `_.reduceRight`, without support
- * for iteratee shorthands, which iterates over `collection` using `eachFunc`.
+ * The base implementation of `_.reduce` and `_.reduceRight` which iterates
+ * over `collection` using `eachFunc`.
  *
  * @private
  * @param {Array|Object} collection The collection to iterate over.
diff --git a/_baseSome.js b/_baseSome.js
index 7db1a7b6d..7b1b5246b 100644
--- a/_baseSome.js
+++ b/_baseSome.js
@@ -1,7 +1,7 @@
 import baseEach from './_baseEach.js';
 
 /**
- * The base implementation of `_.some` without support for iteratee shorthands.
+ * The base implementation of `_.some`.
  *
  * @private
  * @param {Array|Object} collection The collection to iterate over.
diff --git a/_baseSortedUniq.js b/_baseSortedUniq.js
index d4bf82fad..fe00745bc 100644
--- a/_baseSortedUniq.js
+++ b/_baseSortedUniq.js
@@ -1,8 +1,7 @@
 import eq from './eq.js';
 
 /**
- * The base implementation of `_.sortedUniq` and `_.sortedUniqBy` without
- * support for iteratee shorthands.
+ * The base implementation of `_.sortedUniq` and `_.sortedUniqBy`.
  *
  * @private
  * @param {Array} array The array to inspect.
diff --git a/_baseSum.js b/_baseSum.js
index 9d79920f7..b82fc04be 100644
--- a/_baseSum.js
+++ b/_baseSum.js
@@ -1,6 +1,5 @@
 /**
- * The base implementation of `_.sum` and `_.sumBy` without support for
- * iteratee shorthands.
+ * The base implementation of `_.sum` and `_.sumBy`.
  *
  * @private
  * @param {Array} array The array to iterate over.
diff --git a/_baseTimes.js b/_baseTimes.js
index e4954747e..09c1c447e 100644
--- a/_baseTimes.js
+++ b/_baseTimes.js
@@ -1,6 +1,5 @@
 /**
- * The base implementation of `_.times` without support for iteratee shorthands
- * or max array length checks.
+ * The base implementation of `_.times` without support for max array length checks.
  *
  * @private
  * @param {number} n The number of times to invoke `iteratee`.
diff --git a/_baseUniq.js b/_baseUniq.js
index fde5ed1e1..acf3c6736 100644
--- a/_baseUniq.js
+++ b/_baseUniq.js
@@ -9,7 +9,7 @@ import setToArray from './_setToArray.js';
 const LARGE_ARRAY_SIZE = 200;
 
 /**
- * The base implementation of `_.uniqBy` without support for iteratee shorthands.
+ * The base implementation of `_.uniqBy`.
  *
  * @private
  * @param {Array} array The array to inspect.
diff --git a/_baseWhile.js b/_baseWhile.js
index d9fbe0c4a..3adb8ace6 100644
--- a/_baseWhile.js
+++ b/_baseWhile.js
@@ -1,8 +1,7 @@
 import baseSlice from './_baseSlice.js';
 
 /**
- * The base implementation of methods like `_.dropWhile` and `_.takeWhile`
- * without support for iteratee shorthands.
+ * The base implementation of methods like `_.dropWhile` and `_.takeWhile`.
  *
  * @private
  * @param {Array} array The array to query.
diff --git a/_baseXor.js b/_baseXor.js
index 8509f3807..5fd3f68b1 100644
--- a/_baseXor.js
+++ b/_baseXor.js
@@ -3,8 +3,8 @@ import baseFlatten from './_baseFlatten.js';
 import baseUniq from './_baseUniq.js';
 
 /**
- * The base implementation of methods like `_.xor`, without support for
- * iteratee shorthands, that accepts an array of arrays to inspect.
+ * The base implementation of methods like `_.xor` which accepts an array of
+ * arrays to inspect.
  *
  * @private
  * @param {Array} arrays The arrays to inspect.
diff --git a/_castFunction.js b/_castFunction.js
deleted file mode 100644
index 03a2e9913..000000000
--- a/_castFunction.js
+++ /dev/null
@@ -1,14 +0,0 @@
-import identity from './identity.js';
-
-/**
- * Casts `value` to `identity` if it's not a function.
- *
- * @private
- * @param {*} value The value to inspect.
- * @returns {Function} Returns cast function.
- */
-function castFunction(value) {
-  return typeof value == 'function' ? value : identity;
-}
-
-export default castFunction;
diff --git a/_createAggregator.js b/_createAggregator.js
index 37c5b1591..b35b374d8 100644
--- a/_createAggregator.js
+++ b/_createAggregator.js
@@ -1,6 +1,5 @@
 import arrayAggregator from './_arrayAggregator.js';
 import baseAggregator from './_baseAggregator.js';
-import baseIteratee from './_baseIteratee.js';
 import isArray from './isArray.js';
 
 /**
@@ -15,7 +14,7 @@ function createAggregator(setter, initializer) {
   return (collection, iteratee) => {
     const func = isArray(collection) ? arrayAggregator : baseAggregator;
     const accumulator = initializer ? initializer() : {};
-    return func(collection, setter, baseIteratee(iteratee, 2), accumulator);
+    return func(collection, setter, iteratee, accumulator);
   };
 }
 
diff --git a/_createFind.js b/_createFind.js
index ef0182a67..eb31fed6a 100644
--- a/_createFind.js
+++ b/_createFind.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import isArrayLike from './isArrayLike.js';
 import keys from './keys.js';
 
@@ -14,7 +13,6 @@ function createFind(findIndexFunc) {
     let iteratee;
     const iterable = Object(collection);
     if (!isArrayLike(collection)) {
-      iteratee = baseIteratee(predicate, 3);
       collection = keys(collection);
       predicate = key => iteratee(iterable[key], key, iterable);
     }
diff --git a/_createInverter.js b/_createInverter.js
index 939c43a16..0f2d181d2 100644
--- a/_createInverter.js
+++ b/_createInverter.js
@@ -5,11 +5,10 @@ import baseInverter from './_baseInverter.js';
  *
  * @private
  * @param {Function} setter The function to set accumulator values.
- * @param {Function} toIteratee The function to resolve iteratees.
  * @returns {Function} Returns the new inverter function.
  */
-function createInverter(setter, toIteratee) {
-  return (object, iteratee) => baseInverter(object, setter, toIteratee(iteratee), {});
+function createInverter(setter) {
+  return (object, iteratee) => baseInverter(object, setter, iteratee, {});
 }
 
 export default createInverter;
diff --git a/_createOver.js b/_createOver.js
index ae55b3a0b..35c32f061 100644
--- a/_createOver.js
+++ b/_createOver.js
@@ -1,6 +1,4 @@
 import apply from './_apply.js';
-import arrayMap from './_arrayMap.js';
-import baseIteratee from './_baseIteratee.js';
 
 /**
  * Creates a function like `_.over`.
@@ -11,8 +9,7 @@ import baseIteratee from './_baseIteratee.js';
  */
 function createOver(arrayFunc) {
   return (...iteratees) => {
-    iteratees = arrayMap(iteratees, iteratee => baseIteratee(iteratee));
-    return (...args) => {
+    return function(...args) {
       const thisArg = this;
       return arrayFunc(iteratees, iteratee => apply(iteratee, thisArg, args));
     };
diff --git a/cond.js b/cond.js
index 15075e889..00f217d25 100644
--- a/cond.js
+++ b/cond.js
@@ -1,6 +1,5 @@
 import apply from './_apply.js';
 import arrayMap from './_arrayMap.js';
-import baseIteratee from './_baseIteratee.js';
 
 /** Error message constants. */
 const FUNC_ERROR_TEXT = 'Expected a function';
@@ -36,13 +35,12 @@ const FUNC_ERROR_TEXT = 'Expected a function';
  */
 function cond(pairs) {
   const length = pairs == null ? 0 : pairs.length;
-  const toIteratee = baseIteratee;
 
   pairs = !length ? [] : arrayMap(pairs, pair => {
     if (typeof pair[1] != 'function') {
       throw new TypeError(FUNC_ERROR_TEXT);
     }
-    return [toIteratee(pair[0]), pair[1]];
+    return [pair[0], pair[1]];
   });
 
   return (...args) => {
diff --git a/countBy.js b/countBy.js
index 98def343e..66f198e35 100644
--- a/countBy.js
+++ b/countBy.js
@@ -18,16 +18,12 @@ const hasOwnProperty = objectProto.hasOwnProperty;
  * @since 0.5.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The iteratee to transform keys.
+ * @param {Function} iteratee The iteratee to transform keys.
  * @returns {Object} Returns the composed aggregate object.
  * @example
  *
  * _.countBy([6.1, 4.2, 6.3], Math.floor);
  * // => { '4': 1, '6': 2 }
- *
- * // The `_.property` iteratee shorthand.
- * _.countBy(['one', 'two', 'three'], 'length');
- * // => { '3': 2, '5': 1 }
  */
 const countBy = createAggregator((result, value, key) => {
   if (hasOwnProperty.call(result, key)) {
diff --git a/differenceBy.js b/differenceBy.js
index d0629aee4..28a9ae20f 100644
--- a/differenceBy.js
+++ b/differenceBy.js
@@ -1,6 +1,5 @@
 import baseDifference from './_baseDifference.js';
 import baseFlatten from './_baseFlatten.js';
-import baseIteratee from './_baseIteratee.js';
 import isArrayLikeObject from './isArrayLikeObject.js';
 import last from './last.js';
 
@@ -19,16 +18,12 @@ import last from './last.js';
  * @category Array
  * @param {Array} array The array to inspect.
  * @param {...Array} [values] The values to exclude.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {Array} Returns the new array of filtered values.
  * @example
  *
  * _.differenceBy([2.1, 1.2], [2.3, 3.4], Math.floor);
  * // => [1.2]
- *
- * // The `_.property` iteratee shorthand.
- * _.differenceBy([{ 'x': 2 }, { 'x': 1 }], [{ 'x': 1 }], 'x');
- * // => [{ 'x': 2 }]
  */
 function differenceBy(array, ...values) {
   let iteratee = last(values);
@@ -36,7 +31,7 @@ function differenceBy(array, ...values) {
     iteratee = undefined;
   }
   return isArrayLikeObject(array)
-    ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), baseIteratee(iteratee, 2))
+    ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), iteratee)
     : [];
 }
 
diff --git a/dropRightWhile.js b/dropRightWhile.js
index c5cdbc6c1..8d9814f59 100644
--- a/dropRightWhile.js
+++ b/dropRightWhile.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import baseWhile from './_baseWhile.js';
 
 /**
@@ -11,7 +10,7 @@ import baseWhile from './_baseWhile.js';
  * @since 3.0.0
  * @category Array
  * @param {Array} array The array to query.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @returns {Array} Returns the slice of `array`.
  * @example
  *
@@ -23,22 +22,10 @@ import baseWhile from './_baseWhile.js';
  *
  * _.dropRightWhile(users, function(o) { return !o.active; });
  * // => objects for ['barney']
- *
- * // The `_.matches` iteratee shorthand.
- * _.dropRightWhile(users, { 'user': 'pebbles', 'active': false });
- * // => objects for ['barney', 'fred']
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.dropRightWhile(users, ['active', false]);
- * // => objects for ['barney']
- *
- * // The `_.property` iteratee shorthand.
- * _.dropRightWhile(users, 'active');
- * // => objects for ['barney', 'fred', 'pebbles']
  */
 function dropRightWhile(array, predicate) {
   return (array && array.length)
-    ? baseWhile(array, baseIteratee(predicate, 3), true, true)
+    ? baseWhile(array, predicate, true, true)
     : [];
 }
 
diff --git a/dropWhile.js b/dropWhile.js
index 688c4dccd..62d058f31 100644
--- a/dropWhile.js
+++ b/dropWhile.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import baseWhile from './_baseWhile.js';
 
 /**
@@ -11,7 +10,7 @@ import baseWhile from './_baseWhile.js';
  * @since 3.0.0
  * @category Array
  * @param {Array} array The array to query.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @returns {Array} Returns the slice of `array`.
  * @example
  *
@@ -23,22 +22,10 @@ import baseWhile from './_baseWhile.js';
  *
  * _.dropWhile(users, function(o) { return !o.active; });
  * // => objects for ['pebbles']
- *
- * // The `_.matches` iteratee shorthand.
- * _.dropWhile(users, { 'user': 'barney', 'active': false });
- * // => objects for ['fred', 'pebbles']
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.dropWhile(users, ['active', false]);
- * // => objects for ['pebbles']
- *
- * // The `_.property` iteratee shorthand.
- * _.dropWhile(users, 'active');
- * // => objects for ['barney', 'fred', 'pebbles']
  */
 function dropWhile(array, predicate) {
   return (array && array.length)
-    ? baseWhile(array, baseIteratee(predicate, 3), true)
+    ? baseWhile(array, predicate, true)
     : [];
 }
 
diff --git a/every.js b/every.js
index 61bf5f349..1cc28cde7 100644
--- a/every.js
+++ b/every.js
@@ -1,6 +1,5 @@
 import arrayEvery from './_arrayEvery.js';
 import baseEvery from './_baseEvery.js';
-import baseIteratee from './_baseIteratee.js';
 import isArray from './isArray.js';
 import isIterateeCall from './_isIterateeCall.js';
 
@@ -19,7 +18,7 @@ import isIterateeCall from './_isIterateeCall.js';
  * @since 0.1.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
  * @returns {boolean} Returns `true` if all elements pass the predicate check,
  *  else `false`.
@@ -27,30 +26,13 @@ import isIterateeCall from './_isIterateeCall.js';
  *
  * _.every([true, 1, null, 'yes'], Boolean);
  * // => false
- *
- * var users = [
- *   { 'user': 'barney', 'age': 36, 'active': false },
- *   { 'user': 'fred',   'age': 40, 'active': false }
- * ];
- *
- * // The `_.matches` iteratee shorthand.
- * _.every(users, { 'user': 'barney', 'active': false });
- * // => false
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.every(users, ['active', false]);
- * // => true
- *
- * // The `_.property` iteratee shorthand.
- * _.every(users, 'active');
- * // => false
  */
 function every(collection, predicate, guard) {
   const func = isArray(collection) ? arrayEvery : baseEvery;
   if (guard && isIterateeCall(collection, predicate, guard)) {
     predicate = undefined;
   }
-  return func(collection, baseIteratee(predicate, 3));
+  return func(collection, predicate);
 }
 
 export default every;
diff --git a/filter.js b/filter.js
index 8c4073682..fc5aa3d93 100644
--- a/filter.js
+++ b/filter.js
@@ -1,6 +1,5 @@
 import arrayFilter from './_arrayFilter.js';
 import baseFilter from './_baseFilter.js';
-import baseIteratee from './_baseIteratee.js';
 import isArray from './isArray.js';
 
 /**
@@ -15,7 +14,7 @@ import isArray from './isArray.js';
  * @since 0.1.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @returns {Array} Returns the new filtered array.
  * @see _.reject
  * @example
@@ -27,22 +26,10 @@ import isArray from './isArray.js';
  *
  * _.filter(users, function(o) { return !o.active; });
  * // => objects for ['fred']
- *
- * // The `_.matches` iteratee shorthand.
- * _.filter(users, { 'age': 36, 'active': true });
- * // => objects for ['barney']
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.filter(users, ['active', false]);
- * // => objects for ['fred']
- *
- * // The `_.property` iteratee shorthand.
- * _.filter(users, 'active');
- * // => objects for ['barney']
  */
 function filter(collection, predicate) {
   const func = isArray(collection) ? arrayFilter : baseFilter;
-  return func(collection, baseIteratee(predicate, 3));
+  return func(collection, predicate);
 }
 
 export default filter;
diff --git a/find.js b/find.js
index d7dab9c25..42767ba28 100644
--- a/find.js
+++ b/find.js
@@ -11,7 +11,7 @@ import findIndex from './findIndex.js';
  * @since 0.1.0
  * @category Collection
  * @param {Array|Object} collection The collection to inspect.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @param {number} [fromIndex=0] The index to search from.
  * @returns {*} Returns the matched element, else `undefined`.
  * @example
@@ -24,18 +24,6 @@ import findIndex from './findIndex.js';
  *
  * _.find(users, function(o) { return o.age < 40; });
  * // => object for 'barney'
- *
- * // The `_.matches` iteratee shorthand.
- * _.find(users, { 'age': 1, 'active': true });
- * // => object for 'pebbles'
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.find(users, ['active', false]);
- * // => object for 'fred'
- *
- * // The `_.property` iteratee shorthand.
- * _.find(users, 'active');
- * // => object for 'barney'
  */
 const find = createFind(findIndex);
 
diff --git a/findIndex.js b/findIndex.js
index 15fa25620..2223959f9 100644
--- a/findIndex.js
+++ b/findIndex.js
@@ -1,5 +1,4 @@
 import baseFindIndex from './_baseFindIndex.js';
-import baseIteratee from './_baseIteratee.js';
 import toInteger from './toInteger.js';
 
 /* Built-in method references for those with the same name as other `lodash` methods. */
@@ -14,7 +13,7 @@ const nativeMax = Math.max;
  * @since 1.1.0
  * @category Array
  * @param {Array} array The array to inspect.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @param {number} [fromIndex=0] The index to search from.
  * @returns {number} Returns the index of the found element, else `-1`.
  * @example
@@ -27,18 +26,6 @@ const nativeMax = Math.max;
  *
  * _.findIndex(users, function(o) { return o.user == 'barney'; });
  * // => 0
- *
- * // The `_.matches` iteratee shorthand.
- * _.findIndex(users, { 'user': 'fred', 'active': false });
- * // => 1
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.findIndex(users, ['active', false]);
- * // => 0
- *
- * // The `_.property` iteratee shorthand.
- * _.findIndex(users, 'active');
- * // => 2
  */
 function findIndex(array, predicate, fromIndex) {
   const length = array == null ? 0 : array.length;
@@ -49,7 +36,7 @@ function findIndex(array, predicate, fromIndex) {
   if (index < 0) {
     index = nativeMax(length + index, 0);
   }
-  return baseFindIndex(array, baseIteratee(predicate, 3), index);
+  return baseFindIndex(array, predicate, index);
 }
 
 export default findIndex;
diff --git a/findKey.js b/findKey.js
index a578ede4e..caf489712 100644
--- a/findKey.js
+++ b/findKey.js
@@ -1,6 +1,5 @@
 import baseFindKey from './_baseFindKey.js';
 import baseForOwn from './_baseForOwn.js';
-import baseIteratee from './_baseIteratee.js';
 
 /**
  * This method is like `_.find` except that it returns the key of the first
@@ -11,7 +10,7 @@ import baseIteratee from './_baseIteratee.js';
  * @since 1.1.0
  * @category Object
  * @param {Object} object The object to inspect.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @returns {string|undefined} Returns the key of the matched element,
  *  else `undefined`.
  * @example
@@ -24,21 +23,9 @@ import baseIteratee from './_baseIteratee.js';
  *
  * _.findKey(users, function(o) { return o.age < 40; });
  * // => 'barney' (iteration order is not guaranteed)
- *
- * // The `_.matches` iteratee shorthand.
- * _.findKey(users, { 'age': 1, 'active': true });
- * // => 'pebbles'
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.findKey(users, ['active', false]);
- * // => 'fred'
- *
- * // The `_.property` iteratee shorthand.
- * _.findKey(users, 'active');
- * // => 'barney'
  */
 function findKey(object, predicate) {
-  return baseFindKey(object, baseIteratee(predicate, 3), baseForOwn);
+  return baseFindKey(object, predicate, baseForOwn);
 }
 
 export default findKey;
diff --git a/findLast.js b/findLast.js
index 23d408efa..b80f36e1f 100644
--- a/findLast.js
+++ b/findLast.js
@@ -10,7 +10,7 @@ import findLastIndex from './findLastIndex.js';
  * @since 2.0.0
  * @category Collection
  * @param {Array|Object} collection The collection to inspect.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @param {number} [fromIndex=collection.length-1] The index to search from.
  * @returns {*} Returns the matched element, else `undefined`.
  * @example
diff --git a/findLastIndex.js b/findLastIndex.js
index a17dafd57..877dd3e29 100644
--- a/findLastIndex.js
+++ b/findLastIndex.js
@@ -1,5 +1,4 @@
 import baseFindIndex from './_baseFindIndex.js';
-import baseIteratee from './_baseIteratee.js';
 import toInteger from './toInteger.js';
 
 /* Built-in method references for those with the same name as other `lodash` methods. */
@@ -15,7 +14,7 @@ const nativeMin = Math.min;
  * @since 2.0.0
  * @category Array
  * @param {Array} array The array to inspect.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @param {number} [fromIndex=array.length-1] The index to search from.
  * @returns {number} Returns the index of the found element, else `-1`.
  * @example
@@ -28,18 +27,6 @@ const nativeMin = Math.min;
  *
  * _.findLastIndex(users, function(o) { return o.user == 'pebbles'; });
  * // => 2
- *
- * // The `_.matches` iteratee shorthand.
- * _.findLastIndex(users, { 'user': 'barney', 'active': true });
- * // => 0
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.findLastIndex(users, ['active', false]);
- * // => 2
- *
- * // The `_.property` iteratee shorthand.
- * _.findLastIndex(users, 'active');
- * // => 0
  */
 function findLastIndex(array, predicate, fromIndex) {
   const length = array == null ? 0 : array.length;
@@ -53,7 +40,7 @@ function findLastIndex(array, predicate, fromIndex) {
       ? nativeMax(length + index, 0)
       : nativeMin(index, length - 1);
   }
-  return baseFindIndex(array, baseIteratee(predicate, 3), index, true);
+  return baseFindIndex(array, predicate, index, true);
 }
 
 export default findLastIndex;
diff --git a/findLastKey.js b/findLastKey.js
index 6b391dc03..95022ffd6 100644
--- a/findLastKey.js
+++ b/findLastKey.js
@@ -1,6 +1,5 @@
 import baseFindKey from './_baseFindKey.js';
 import baseForOwnRight from './_baseForOwnRight.js';
-import baseIteratee from './_baseIteratee.js';
 
 /**
  * This method is like `_.findKey` except that it iterates over elements of
@@ -11,7 +10,7 @@ import baseIteratee from './_baseIteratee.js';
  * @since 2.0.0
  * @category Object
  * @param {Object} object The object to inspect.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @returns {string|undefined} Returns the key of the matched element,
  *  else `undefined`.
  * @example
@@ -24,21 +23,9 @@ import baseIteratee from './_baseIteratee.js';
  *
  * _.findLastKey(users, function(o) { return o.age < 40; });
  * // => returns 'pebbles' assuming `_.findKey` returns 'barney'
- *
- * // The `_.matches` iteratee shorthand.
- * _.findLastKey(users, { 'age': 36, 'active': true });
- * // => 'barney'
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.findLastKey(users, ['active', false]);
- * // => 'fred'
- *
- * // The `_.property` iteratee shorthand.
- * _.findLastKey(users, 'active');
- * // => 'pebbles'
  */
 function findLastKey(object, predicate) {
-  return baseFindKey(object, baseIteratee(predicate, 3), baseForOwnRight);
+  return baseFindKey(object, predicate, baseForOwnRight);
 }
 
 export default findLastKey;
diff --git a/flatMap.js b/flatMap.js
index 52a6a7aeb..8e6b56643 100644
--- a/flatMap.js
+++ b/flatMap.js
@@ -11,7 +11,7 @@ import map from './map.js';
  * @since 4.0.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Array} Returns the new flattened array.
  * @example
  *
diff --git a/flatMapDeep.js b/flatMapDeep.js
index 59f54621a..3e292a4b1 100644
--- a/flatMapDeep.js
+++ b/flatMapDeep.js
@@ -13,7 +13,7 @@ const INFINITY = 1 / 0;
  * @since 4.7.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Array} Returns the new flattened array.
  * @example
  *
diff --git a/flatMapDepth.js b/flatMapDepth.js
index 4be00964c..6200b6bd1 100644
--- a/flatMapDepth.js
+++ b/flatMapDepth.js
@@ -11,7 +11,7 @@ import toInteger from './toInteger.js';
  * @since 4.7.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @param {number} [depth=1] The maximum recursion depth.
  * @returns {Array} Returns the new flattened array.
  * @example
diff --git a/forEach.js b/forEach.js
index 15f9780f3..19fe274f0 100644
--- a/forEach.js
+++ b/forEach.js
@@ -1,6 +1,5 @@
 import arrayEach from './_arrayEach.js';
-import baseEach from './_baseEach.js';
-import castFunction from './_castFunction.js';
+import baseEach from './_baseEach.js';;
 import isArray from './isArray.js';
 
 /**
@@ -18,7 +17,7 @@ import isArray from './isArray.js';
  * @alias each
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Array|Object} Returns `collection`.
  * @see _.forEachRight
  * @example
@@ -35,7 +34,7 @@ import isArray from './isArray.js';
  */
 function forEach(collection, iteratee) {
   const func = isArray(collection) ? arrayEach : baseEach;
-  return func(collection, castFunction(iteratee));
+  return func(collection, iteratee);
 }
 
 export default forEach;
diff --git a/forEachRight.js b/forEachRight.js
index cb12c147a..7b1191376 100644
--- a/forEachRight.js
+++ b/forEachRight.js
@@ -1,6 +1,5 @@
 import arrayEachRight from './_arrayEachRight.js';
 import baseEachRight from './_baseEachRight.js';
-import castFunction from './_castFunction.js';
 import isArray from './isArray.js';
 
 /**
@@ -13,7 +12,7 @@ import isArray from './isArray.js';
  * @alias eachRight
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Array|Object} Returns `collection`.
  * @see _.forEach
  * @example
@@ -25,7 +24,7 @@ import isArray from './isArray.js';
  */
 function forEachRight(collection, iteratee) {
   const func = isArray(collection) ? arrayEachRight : baseEachRight;
-  return func(collection, castFunction(iteratee));
+  return func(collection, iteratee);
 }
 
 export default forEachRight;
diff --git a/forIn.js b/forIn.js
index 436f319d2..0fac23bad 100644
--- a/forIn.js
+++ b/forIn.js
@@ -1,5 +1,4 @@
 import baseFor from './_baseFor.js';
-import castFunction from './_castFunction.js';
 import keysIn from './keysIn.js';
 
 /**
@@ -13,7 +12,7 @@ import keysIn from './keysIn.js';
  * @since 0.3.0
  * @category Object
  * @param {Object} object The object to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Object} Returns `object`.
  * @see _.forInRight
  * @example
@@ -31,9 +30,7 @@ import keysIn from './keysIn.js';
  * // => Logs 'a', 'b', then 'c' (iteration order is not guaranteed).
  */
 function forIn(object, iteratee) {
-  return object == null
-    ? object
-    : baseFor(object, castFunction(iteratee), keysIn);
+  return object == null ? object : baseFor(object, iteratee, keysIn);
 }
 
 export default forIn;
diff --git a/forInRight.js b/forInRight.js
index cc92970fb..3b68d768a 100644
--- a/forInRight.js
+++ b/forInRight.js
@@ -1,5 +1,4 @@
 import baseForRight from './_baseForRight.js';
-import castFunction from './_castFunction.js';
 import keysIn from './keysIn.js';
 
 /**
@@ -11,7 +10,7 @@ import keysIn from './keysIn.js';
  * @since 2.0.0
  * @category Object
  * @param {Object} object The object to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Object} Returns `object`.
  * @see _.forIn
  * @example
@@ -29,9 +28,7 @@ import keysIn from './keysIn.js';
  * // => Logs 'c', 'b', then 'a' assuming `_.forIn` logs 'a', 'b', then 'c'.
  */
 function forInRight(object, iteratee) {
-  return object == null
-    ? object
-    : baseForRight(object, castFunction(iteratee), keysIn);
+  return object == null ? object : baseForRight(object, iteratee, keysIn);
 }
 
 export default forInRight;
diff --git a/forOwn.js b/forOwn.js
index fe661690c..71b98b340 100644
--- a/forOwn.js
+++ b/forOwn.js
@@ -1,5 +1,4 @@
 import baseForOwn from './_baseForOwn.js';
-import castFunction from './_castFunction.js';
 
 /**
  * Iterates over own enumerable string keyed properties of an object and
@@ -12,7 +11,7 @@ import castFunction from './_castFunction.js';
  * @since 0.3.0
  * @category Object
  * @param {Object} object The object to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Object} Returns `object`.
  * @see _.forOwnRight
  * @example
@@ -30,7 +29,7 @@ import castFunction from './_castFunction.js';
  * // => Logs 'a' then 'b' (iteration order is not guaranteed).
  */
 function forOwn(object, iteratee) {
-  return object && baseForOwn(object, castFunction(iteratee));
+  return object && baseForOwn(object, iteratee);
 }
 
 export default forOwn;
diff --git a/forOwnRight.js b/forOwnRight.js
index fe2dd281a..f93234de4 100644
--- a/forOwnRight.js
+++ b/forOwnRight.js
@@ -1,5 +1,4 @@
 import baseForOwnRight from './_baseForOwnRight.js';
-import castFunction from './_castFunction.js';
 
 /**
  * This method is like `_.forOwn` except that it iterates over properties of
@@ -10,7 +9,7 @@ import castFunction from './_castFunction.js';
  * @since 2.0.0
  * @category Object
  * @param {Object} object The object to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Object} Returns `object`.
  * @see _.forOwn
  * @example
@@ -28,7 +27,7 @@ import castFunction from './_castFunction.js';
  * // => Logs 'b' then 'a' assuming `_.forOwn` logs 'a' then 'b'.
  */
 function forOwnRight(object, iteratee) {
-  return object && baseForOwnRight(object, castFunction(iteratee));
+  return object && baseForOwnRight(object, iteratee);
 }
 
 export default forOwnRight;
diff --git a/groupBy.js b/groupBy.js
index 4ab3cd924..5fa8bf87c 100644
--- a/groupBy.js
+++ b/groupBy.js
@@ -19,16 +19,12 @@ const hasOwnProperty = objectProto.hasOwnProperty;
  * @since 0.1.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The iteratee to transform keys.
+ * @param {Function} iteratee The iteratee to transform keys.
  * @returns {Object} Returns the composed aggregate object.
  * @example
  *
  * _.groupBy([6.1, 4.2, 6.3], Math.floor);
  * // => { '4': [4.2], '6': [6.1, 6.3] }
- *
- * // The `_.property` iteratee shorthand.
- * _.groupBy(['one', 'two', 'three'], 'length');
- * // => { '3': ['one', 'two'], '5': ['three'] }
  */
 const groupBy = createAggregator((result, value, key) => {
   if (hasOwnProperty.call(result, key)) {
diff --git a/intersectionBy.js b/intersectionBy.js
index 794a78f4f..f81d1382f 100644
--- a/intersectionBy.js
+++ b/intersectionBy.js
@@ -1,6 +1,5 @@
 import arrayMap from './_arrayMap.js';
 import baseIntersection from './_baseIntersection.js';
-import baseIteratee from './_baseIteratee.js';
 import castArrayLikeObject from './_castArrayLikeObject.js';
 import last from './last.js';
 
@@ -16,16 +15,12 @@ import last from './last.js';
  * @since 4.0.0
  * @category Array
  * @param {...Array} [arrays] The arrays to inspect.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {Array} Returns the new array of intersecting values.
  * @example
  *
  * _.intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor);
  * // => [2.1]
- *
- * // The `_.property` iteratee shorthand.
- * _.intersectionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
- * // => [{ 'x': 1 }]
  */
 function intersectionBy(...arrays) {
   let iteratee = last(arrays);
@@ -37,7 +32,7 @@ function intersectionBy(...arrays) {
     mapped.pop();
   }
   return (mapped.length && mapped[0] === arrays[0])
-    ? baseIntersection(mapped, baseIteratee(iteratee, 2))
+    ? baseIntersection(mapped, iteratee)
     : [];
 }
 
diff --git a/invert.js b/invert.js
index 8ba4c3b24..ccc08fe34 100644
--- a/invert.js
+++ b/invert.js
@@ -22,6 +22,6 @@ import identity from './identity.js';
  */
 const invert = createInverter((result, value, key) => {
   result[value] = key;
-}, constant(identity));
+});
 
 export default invert;
diff --git a/invertBy.js b/invertBy.js
index c9b85259a..eabae038a 100644
--- a/invertBy.js
+++ b/invertBy.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import createInverter from './_createInverter.js';
 
 /** Used for built-in method references. */
@@ -19,15 +18,12 @@ const hasOwnProperty = objectProto.hasOwnProperty;
  * @since 4.1.0
  * @category Object
  * @param {Object} object The object to invert.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {Object} Returns the new inverted object.
  * @example
  *
  * var object = { 'a': 1, 'b': 2, 'c': 1 };
  *
- * _.invertBy(object);
- * // => { '1': ['a', 'c'], '2': ['b'] }
- *
  * _.invertBy(object, function(value) {
  *   return 'group' + value;
  * });
@@ -39,6 +35,6 @@ const invertBy = createInverter((result, value, key) => {
   } else {
     result[value] = [key];
   }
-}, baseIteratee);
+});
 
 export default invertBy;
diff --git a/keyBy.js b/keyBy.js
index 13b34e79b..e64f7ec86 100644
--- a/keyBy.js
+++ b/keyBy.js
@@ -12,7 +12,7 @@ import createAggregator from './_createAggregator.js';
  * @since 4.0.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The iteratee to transform keys.
+ * @param {Function} iteratee The iteratee to transform keys.
  * @returns {Object} Returns the composed aggregate object.
  * @example
  *
diff --git a/map.js b/map.js
index 975fea381..9daf124b7 100644
--- a/map.js
+++ b/map.js
@@ -1,5 +1,4 @@
 import arrayMap from './_arrayMap.js';
-import baseIteratee from './_baseIteratee.js';
 import baseMap from './_baseMap.js';
 import isArray from './isArray.js';
 
@@ -22,7 +21,7 @@ import isArray from './isArray.js';
  * @since 0.1.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Array} Returns the new mapped array.
  * @example
  *
@@ -35,19 +34,10 @@ import isArray from './isArray.js';
  *
  * _.map({ 'a': 4, 'b': 8 }, square);
  * // => [16, 64] (iteration order is not guaranteed)
- *
- * var users = [
- *   { 'user': 'barney' },
- *   { 'user': 'fred' }
- * ];
- *
- * // The `_.property` iteratee shorthand.
- * _.map(users, 'user');
- * // => ['barney', 'fred']
  */
 function map(collection, iteratee) {
   const func = isArray(collection) ? arrayMap : baseMap;
-  return func(collection, baseIteratee(iteratee, 3));
+  return func(collection, iteratee);
 }
 
 export default map;
diff --git a/mapKeys.js b/mapKeys.js
index 0d8969a7a..f578519b9 100644
--- a/mapKeys.js
+++ b/mapKeys.js
@@ -1,6 +1,5 @@
 import baseAssignValue from './_baseAssignValue.js';
 import baseForOwn from './_baseForOwn.js';
-import baseIteratee from './_baseIteratee.js';
 
 /**
  * The opposite of `_.mapValues`; this method creates an object with the
@@ -13,7 +12,7 @@ import baseIteratee from './_baseIteratee.js';
  * @since 3.8.0
  * @category Object
  * @param {Object} object The object to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Object} Returns the new mapped object.
  * @see _.mapValues
  * @example
@@ -25,8 +24,6 @@ import baseIteratee from './_baseIteratee.js';
  */
 function mapKeys(object, iteratee) {
   const result = {};
-  iteratee = baseIteratee(iteratee, 3);
-
   baseForOwn(object, (value, key, object) => {
     baseAssignValue(result, iteratee(value, key, object), value);
   });
diff --git a/mapValues.js b/mapValues.js
index 513db9de5..102ba4d6d 100644
--- a/mapValues.js
+++ b/mapValues.js
@@ -1,6 +1,5 @@
 import baseAssignValue from './_baseAssignValue.js';
 import baseForOwn from './_baseForOwn.js';
-import baseIteratee from './_baseIteratee.js';
 
 /**
  * Creates an object with the same keys as `object` and values generated
@@ -13,7 +12,7 @@ import baseIteratee from './_baseIteratee.js';
  * @since 2.4.0
  * @category Object
  * @param {Object} object The object to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Object} Returns the new mapped object.
  * @see _.mapKeys
  * @example
@@ -25,15 +24,9 @@ import baseIteratee from './_baseIteratee.js';
  *
  * _.mapValues(users, function(o) { return o.age; });
  * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
- *
- * // The `_.property` iteratee shorthand.
- * _.mapValues(users, 'age');
- * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
  */
 function mapValues(object, iteratee) {
   const result = {};
-  iteratee = baseIteratee(iteratee, 3);
-
   baseForOwn(object, (value, key, object) => {
     baseAssignValue(result, key, iteratee(value, key, object));
   });
diff --git a/maxBy.js b/maxBy.js
index 6cbd1ceea..e69ac9ac0 100644
--- a/maxBy.js
+++ b/maxBy.js
@@ -1,6 +1,5 @@
 import baseExtremum from './_baseExtremum.js';
 import baseGt from './_baseGt.js';
-import baseIteratee from './_baseIteratee.js';
 
 /**
  * This method is like `_.max` except that it accepts `iteratee` which is
@@ -12,7 +11,7 @@ import baseIteratee from './_baseIteratee.js';
  * @since 4.0.0
  * @category Math
  * @param {Array} array The array to iterate over.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {*} Returns the maximum value.
  * @example
  *
@@ -20,14 +19,10 @@ import baseIteratee from './_baseIteratee.js';
  *
  * _.maxBy(objects, function(o) { return o.n; });
  * // => { 'n': 2 }
- *
- * // The `_.property` iteratee shorthand.
- * _.maxBy(objects, 'n');
- * // => { 'n': 2 }
  */
 function maxBy(array, iteratee) {
   return (array && array.length)
-    ? baseExtremum(array, baseIteratee(iteratee, 2), baseGt)
+    ? baseExtremum(array, iteratee, baseGt)
     : undefined;
 }
 
diff --git a/mean.js b/mean.js
index 2323aefc1..26ee2a958 100644
--- a/mean.js
+++ b/mean.js
@@ -1,4 +1,4 @@
-import baseMean from './_baseMean.js';
+import baseMean from './meanBy.js';
 import identity from './identity.js';
 
 /**
@@ -16,7 +16,7 @@ import identity from './identity.js';
  * // => 5
  */
 function mean(array) {
-  return baseMean(array, identity);
+  return mean(array, identity);
 }
 
 export default mean;
diff --git a/meanBy.js b/meanBy.js
index 4a29ebdc9..d2a4173a5 100644
--- a/meanBy.js
+++ b/meanBy.js
@@ -1,5 +1,7 @@
-import baseIteratee from './_baseIteratee.js';
-import baseMean from './_baseMean.js';
+import baseSum from './_baseSum.js';
+
+/** Used as references for various `Number` constants. */
+const NAN = 0 / 0;
 
 /**
  * This method is like `_.mean` except that it accepts `iteratee` which is
@@ -11,7 +13,7 @@ import baseMean from './_baseMean.js';
  * @since 4.7.0
  * @category Math
  * @param {Array} array The array to iterate over.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {number} Returns the mean.
  * @example
  *
@@ -19,13 +21,10 @@ import baseMean from './_baseMean.js';
  *
  * _.meanBy(objects, function(o) { return o.n; });
  * // => 5
- *
- * // The `_.property` iteratee shorthand.
- * _.meanBy(objects, 'n');
- * // => 5
  */
 function meanBy(array, iteratee) {
-  return baseMean(array, baseIteratee(iteratee, 2));
+  const length = array == null ? 0 : array.length;
+  return length ? (baseSum(array, iteratee) / length) : NAN;
 }
 
 export default meanBy;
diff --git a/minBy.js b/minBy.js
index 2d810a840..0e0e5515e 100644
--- a/minBy.js
+++ b/minBy.js
@@ -1,5 +1,4 @@
 import baseExtremum from './_baseExtremum.js';
-import baseIteratee from './_baseIteratee.js';
 import baseLt from './_baseLt.js';
 
 /**
@@ -12,7 +11,7 @@ import baseLt from './_baseLt.js';
  * @since 4.0.0
  * @category Math
  * @param {Array} array The array to iterate over.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {*} Returns the minimum value.
  * @example
  *
@@ -20,14 +19,10 @@ import baseLt from './_baseLt.js';
  *
  * _.minBy(objects, function(o) { return o.n; });
  * // => { 'n': 1 }
- *
- * // The `_.property` iteratee shorthand.
- * _.minBy(objects, 'n');
- * // => { 'n': 1 }
  */
 function minBy(array, iteratee) {
   return (array && array.length)
-    ? baseExtremum(array, baseIteratee(iteratee, 2), baseLt)
+    ? baseExtremum(array, iteratee, baseLt)
     : undefined;
 }
 
diff --git a/overArgs.js b/overArgs.js
index 187c9e11b..f8942f991 100644
--- a/overArgs.js
+++ b/overArgs.js
@@ -1,7 +1,5 @@
 import apply from './_apply.js';
-import arrayMap from './_arrayMap.js';
 import baseFlatten from './_baseFlatten.js';
-import baseIteratee from './_baseIteratee.js';
 
 /* Built-in method references for those with the same name as other `lodash` methods. */
 const nativeMin = Math.min;
@@ -38,7 +36,6 @@ const nativeMin = Math.min;
  * // => [100, 10]
  */
 function overArgs(func, ...transforms) {
-  transforms = arrayMap(transforms, transform => baseIteratee(transform));
   const funcsLength = transforms.length;
   return function(...args) {
     let index = -1;
diff --git a/partition.js b/partition.js
index 5993de0df..f7babe6da 100644
--- a/partition.js
+++ b/partition.js
@@ -11,7 +11,7 @@ import createAggregator from './_createAggregator.js';
  * @since 3.0.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @returns {Array} Returns the array of grouped elements.
  * @example
  *
@@ -23,18 +23,6 @@ import createAggregator from './_createAggregator.js';
  *
  * _.partition(users, function(o) { return o.active; });
  * // => objects for [['fred'], ['barney', 'pebbles']]
- *
- * // The `_.matches` iteratee shorthand.
- * _.partition(users, { 'age': 1, 'active': false });
- * // => objects for [['pebbles'], ['barney', 'fred']]
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.partition(users, ['active', false]);
- * // => objects for [['barney', 'pebbles'], ['fred']]
- *
- * // The `_.property` iteratee shorthand.
- * _.partition(users, 'active');
- * // => objects for [['fred'], ['barney', 'pebbles']]
  */
 const partition = createAggregator((result, value, key) =>
   result[key ? 0 : 1].push(value), () => [[], []]);
diff --git a/pickBy.js b/pickBy.js
index 3e8680c05..286e18c4b 100644
--- a/pickBy.js
+++ b/pickBy.js
@@ -1,5 +1,4 @@
 import arrayMap from './_arrayMap.js';
-import baseIteratee from './_baseIteratee.js';
 import basePickBy from './_basePickBy.js';
 import getAllKeysIn from './_getAllKeysIn.js';
 
@@ -12,7 +11,7 @@ import getAllKeysIn from './_getAllKeysIn.js';
  * @since 4.0.0
  * @category Object
  * @param {Object} object The source object.
- * @param {Function} [predicate=_.identity] The function invoked per property.
+ * @param {Function} predicate The function invoked per property.
  * @returns {Object} Returns the new object.
  * @example
  *
@@ -26,7 +25,6 @@ function pickBy(object, predicate) {
     return {};
   }
   const props = arrayMap(getAllKeysIn(object), prop => [prop]);
-  predicate = baseIteratee(predicate);
   return basePickBy(object, props, (value, path) => predicate(value, path[0]));
 }
 
diff --git a/pullAllBy.js b/pullAllBy.js
index 2f9e41573..142d5e7de 100644
--- a/pullAllBy.js
+++ b/pullAllBy.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import basePullAll from './_basePullAll.js';
 
 /**
@@ -14,7 +13,7 @@ import basePullAll from './_basePullAll.js';
  * @category Array
  * @param {Array} array The array to modify.
  * @param {Array} values The values to remove.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {Array} Returns `array`.
  * @example
  *
@@ -26,7 +25,7 @@ import basePullAll from './_basePullAll.js';
  */
 function pullAllBy(array, values, iteratee) {
   return (array && array.length && values && values.length)
-    ? basePullAll(array, values, baseIteratee(iteratee, 2))
+    ? basePullAll(array, values, iteratee)
     : array;
 }
 
diff --git a/reduce.js b/reduce.js
index 64e6da631..645dfce81 100644
--- a/reduce.js
+++ b/reduce.js
@@ -1,6 +1,5 @@
 import arrayReduce from './_arrayReduce.js';
 import baseEach from './_baseEach.js';
-import baseIteratee from './_baseIteratee.js';
 import baseReduce from './_baseReduce.js';
 import isArray from './isArray.js';
 
@@ -24,7 +23,7 @@ import isArray from './isArray.js';
  * @since 0.1.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @param {*} [accumulator] The initial value.
  * @returns {*} Returns the accumulated value.
  * @see _.reduceRight
@@ -44,8 +43,7 @@ import isArray from './isArray.js';
 function reduce(collection, iteratee, accumulator) {
   const func = isArray(collection) ? arrayReduce : baseReduce;
   const initAccum = arguments.length < 3;
-
-  return func(collection, baseIteratee(iteratee, 4), accumulator, initAccum, baseEach);
+  return func(collection, iteratee, accumulator, initAccum, baseEach);
 }
 
 export default reduce;
diff --git a/reduceRight.js b/reduceRight.js
index 954c7bdc9..241adf6d2 100644
--- a/reduceRight.js
+++ b/reduceRight.js
@@ -1,6 +1,5 @@
 import arrayReduceRight from './_arrayReduceRight.js';
 import baseEachRight from './_baseEachRight.js';
-import baseIteratee from './_baseIteratee.js';
 import baseReduce from './_baseReduce.js';
 import isArray from './isArray.js';
 
@@ -13,7 +12,7 @@ import isArray from './isArray.js';
  * @since 0.1.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @param {*} [accumulator] The initial value.
  * @returns {*} Returns the accumulated value.
  * @see _.reduce
@@ -29,8 +28,7 @@ import isArray from './isArray.js';
 function reduceRight(collection, iteratee, accumulator) {
   const func = isArray(collection) ? arrayReduceRight : baseReduce;
   const initAccum = arguments.length < 3;
-
-  return func(collection, baseIteratee(iteratee, 4), accumulator, initAccum, baseEachRight);
+  return func(collection, iteratee, accumulator, initAccum, baseEachRight);
 }
 
 export default reduceRight;
diff --git a/reject.js b/reject.js
index 9e395bbcc..d3452b055 100644
--- a/reject.js
+++ b/reject.js
@@ -1,6 +1,5 @@
 import arrayFilter from './_arrayFilter.js';
 import baseFilter from './_baseFilter.js';
-import baseIteratee from './_baseIteratee.js';
 import isArray from './isArray.js';
 import negate from './negate.js';
 
@@ -13,7 +12,7 @@ import negate from './negate.js';
  * @since 0.1.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @returns {Array} Returns the new filtered array.
  * @see _.filter
  * @example
@@ -25,22 +24,10 @@ import negate from './negate.js';
  *
  * _.reject(users, function(o) { return !o.active; });
  * // => objects for ['fred']
- *
- * // The `_.matches` iteratee shorthand.
- * _.reject(users, { 'age': 40, 'active': true });
- * // => objects for ['barney']
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.reject(users, ['active', false]);
- * // => objects for ['fred']
- *
- * // The `_.property` iteratee shorthand.
- * _.reject(users, 'active');
- * // => objects for ['barney']
  */
 function reject(collection, predicate) {
   const func = isArray(collection) ? arrayFilter : baseFilter;
-  return func(collection, negate(baseIteratee(predicate, 3)));
+  return func(collection, negate(predicate));
 }
 
 export default reject;
diff --git a/remove.js b/remove.js
index f705cbe7e..cf9e12dca 100644
--- a/remove.js
+++ b/remove.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import basePullAt from './_basePullAt.js';
 
 /**
@@ -14,7 +13,7 @@ import basePullAt from './_basePullAt.js';
  * @since 2.0.0
  * @category Array
  * @param {Array} array The array to modify.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @returns {Array} Returns the new array of removed elements.
  * @example
  *
@@ -38,7 +37,6 @@ function remove(array, predicate) {
   const indexes = [];
   const length = array.length;
 
-  predicate = baseIteratee(predicate, 3);
   while (++index < length) {
     const value = array[index];
     if (predicate(value, index, array)) {
diff --git a/some.js b/some.js
index f998bebcb..311eeeb73 100644
--- a/some.js
+++ b/some.js
@@ -1,5 +1,4 @@
 import arraySome from './_arraySome.js';
-import baseIteratee from './_baseIteratee.js';
 import baseSome from './_baseSome.js';
 import isArray from './isArray.js';
 import isIterateeCall from './_isIterateeCall.js';
@@ -14,7 +13,7 @@ import isIterateeCall from './_isIterateeCall.js';
  * @since 0.1.0
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
  * @returns {boolean} Returns `true` if any element passes the predicate check,
  *  else `false`.
@@ -22,30 +21,13 @@ import isIterateeCall from './_isIterateeCall.js';
  *
  * _.some([null, 0, 'yes', false], Boolean);
  * // => true
- *
- * var users = [
- *   { 'user': 'barney', 'active': true },
- *   { 'user': 'fred',   'active': false }
- * ];
- *
- * // The `_.matches` iteratee shorthand.
- * _.some(users, { 'user': 'barney', 'active': false });
- * // => false
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.some(users, ['active', false]);
- * // => true
- *
- * // The `_.property` iteratee shorthand.
- * _.some(users, 'active');
- * // => true
  */
 function some(collection, predicate, guard) {
   const func = isArray(collection) ? arraySome : baseSome;
   if (guard && isIterateeCall(collection, predicate, guard)) {
     predicate = undefined;
   }
-  return func(collection, baseIteratee(predicate, 3));
+  return func(collection, predicate);
 }
 
 export default some;
diff --git a/sortedIndexBy.js b/sortedIndexBy.js
index b5ee6db89..790497174 100644
--- a/sortedIndexBy.js
+++ b/sortedIndexBy.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import baseSortedIndexBy from './_baseSortedIndexBy.js';
 
 /**
@@ -12,7 +11,7 @@ import baseSortedIndexBy from './_baseSortedIndexBy.js';
  * @category Array
  * @param {Array} array The sorted array to inspect.
  * @param {*} value The value to evaluate.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {number} Returns the index at which `value` should be inserted
  *  into `array`.
  * @example
@@ -21,13 +20,9 @@ import baseSortedIndexBy from './_baseSortedIndexBy.js';
  *
  * _.sortedIndexBy(objects, { 'x': 4 }, function(o) { return o.x; });
  * // => 0
- *
- * // The `_.property` iteratee shorthand.
- * _.sortedIndexBy(objects, { 'x': 4 }, 'x');
- * // => 0
  */
 function sortedIndexBy(array, value, iteratee) {
-  return baseSortedIndexBy(array, value, baseIteratee(iteratee, 2));
+  return baseSortedIndexBy(array, value, iteratee);
 }
 
 export default sortedIndexBy;
diff --git a/sortedLastIndexBy.js b/sortedLastIndexBy.js
index bb84f81b0..9eea27364 100644
--- a/sortedLastIndexBy.js
+++ b/sortedLastIndexBy.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import baseSortedIndexBy from './_baseSortedIndexBy.js';
 
 /**
@@ -12,7 +11,7 @@ import baseSortedIndexBy from './_baseSortedIndexBy.js';
  * @category Array
  * @param {Array} array The sorted array to inspect.
  * @param {*} value The value to evaluate.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {number} Returns the index at which `value` should be inserted
  *  into `array`.
  * @example
@@ -21,13 +20,9 @@ import baseSortedIndexBy from './_baseSortedIndexBy.js';
  *
  * _.sortedLastIndexBy(objects, { 'x': 4 }, function(o) { return o.x; });
  * // => 1
- *
- * // The `_.property` iteratee shorthand.
- * _.sortedLastIndexBy(objects, { 'x': 4 }, 'x');
- * // => 1
  */
 function sortedLastIndexBy(array, value, iteratee) {
-  return baseSortedIndexBy(array, value, baseIteratee(iteratee, 2), true);
+  return baseSortedIndexBy(array, value, iteratee, true);
 }
 
 export default sortedLastIndexBy;
diff --git a/sortedUniqBy.js b/sortedUniqBy.js
index 48894fe51..6fa7c422d 100644
--- a/sortedUniqBy.js
+++ b/sortedUniqBy.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import baseSortedUniq from './_baseSortedUniq.js';
 
 /**
@@ -10,7 +9,7 @@ import baseSortedUniq from './_baseSortedUniq.js';
  * @since 4.0.0
  * @category Array
  * @param {Array} array The array to inspect.
- * @param {Function} [iteratee] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {Array} Returns the new duplicate free array.
  * @example
  *
@@ -19,7 +18,7 @@ import baseSortedUniq from './_baseSortedUniq.js';
  */
 function sortedUniqBy(array, iteratee) {
   return (array && array.length)
-    ? baseSortedUniq(array, baseIteratee(iteratee, 2))
+    ? baseSortedUniq(array, iteratee)
     : [];
 }
 
diff --git a/sumBy.js b/sumBy.js
index 6828c16b7..c740733e1 100644
--- a/sumBy.js
+++ b/sumBy.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import baseSum from './_baseSum.js';
 
 /**
@@ -11,7 +10,7 @@ import baseSum from './_baseSum.js';
  * @since 4.0.0
  * @category Math
  * @param {Array} array The array to iterate over.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {number} Returns the sum.
  * @example
  *
@@ -19,14 +18,10 @@ import baseSum from './_baseSum.js';
  *
  * _.sumBy(objects, function(o) { return o.n; });
  * // => 20
- *
- * // The `_.property` iteratee shorthand.
- * _.sumBy(objects, 'n');
- * // => 20
  */
 function sumBy(array, iteratee) {
   return (array && array.length)
-    ? baseSum(array, baseIteratee(iteratee, 2))
+    ? baseSum(array, iteratee)
     : 0;
 }
 
diff --git a/takeRightWhile.js b/takeRightWhile.js
index 642454336..7a3f1b02e 100644
--- a/takeRightWhile.js
+++ b/takeRightWhile.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import baseWhile from './_baseWhile.js';
 
 /**
@@ -11,7 +10,7 @@ import baseWhile from './_baseWhile.js';
  * @since 3.0.0
  * @category Array
  * @param {Array} array The array to query.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @returns {Array} Returns the slice of `array`.
  * @example
  *
@@ -23,22 +22,10 @@ import baseWhile from './_baseWhile.js';
  *
  * _.takeRightWhile(users, function(o) { return !o.active; });
  * // => objects for ['fred', 'pebbles']
- *
- * // The `_.matches` iteratee shorthand.
- * _.takeRightWhile(users, { 'user': 'pebbles', 'active': false });
- * // => objects for ['pebbles']
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.takeRightWhile(users, ['active', false]);
- * // => objects for ['fred', 'pebbles']
- *
- * // The `_.property` iteratee shorthand.
- * _.takeRightWhile(users, 'active');
- * // => []
  */
 function takeRightWhile(array, predicate) {
   return (array && array.length)
-    ? baseWhile(array, baseIteratee(predicate, 3), false, true)
+    ? baseWhile(array, predicate, false, true)
     : [];
 }
 
diff --git a/takeWhile.js b/takeWhile.js
index f220a6e5e..a16518768 100644
--- a/takeWhile.js
+++ b/takeWhile.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import baseWhile from './_baseWhile.js';
 
 /**
@@ -11,7 +10,7 @@ import baseWhile from './_baseWhile.js';
  * @since 3.0.0
  * @category Array
  * @param {Array} array The array to query.
- * @param {Function} [predicate=_.identity] The function invoked per iteration.
+ * @param {Function} predicate The function invoked per iteration.
  * @returns {Array} Returns the slice of `array`.
  * @example
  *
@@ -23,22 +22,10 @@ import baseWhile from './_baseWhile.js';
  *
  * _.takeWhile(users, function(o) { return !o.active; });
  * // => objects for ['barney', 'fred']
- *
- * // The `_.matches` iteratee shorthand.
- * _.takeWhile(users, { 'user': 'barney', 'active': false });
- * // => objects for ['barney']
- *
- * // The `_.matchesProperty` iteratee shorthand.
- * _.takeWhile(users, ['active', false]);
- * // => objects for ['barney', 'fred']
- *
- * // The `_.property` iteratee shorthand.
- * _.takeWhile(users, 'active');
- * // => []
  */
 function takeWhile(array, predicate) {
   return (array && array.length)
-    ? baseWhile(array, baseIteratee(predicate, 3))
+    ? baseWhile(array, predicate)
     : [];
 }
 
diff --git a/times.js b/times.js
index 935985a53..c301f0fe2 100644
--- a/times.js
+++ b/times.js
@@ -1,5 +1,4 @@
 import baseTimes from './_baseTimes.js';
-import castFunction from './_castFunction.js';
 import toInteger from './toInteger.js';
 
 /** Used as references for various `Number` constants. */
@@ -20,7 +19,7 @@ const nativeMin = Math.min;
  * @memberOf _
  * @category Util
  * @param {number} n The number of times to invoke `iteratee`.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {Array} Returns the array of results.
  * @example
  *
@@ -37,11 +36,9 @@ function times(n, iteratee) {
   }
   let index = MAX_ARRAY_LENGTH;
   const length = nativeMin(n, MAX_ARRAY_LENGTH);
-
-  iteratee = castFunction(iteratee);
-  n -= MAX_ARRAY_LENGTH;
-
   const result = baseTimes(length, iteratee);
+
+  n -= MAX_ARRAY_LENGTH;
   while (++index < n) {
     iteratee(index);
   }
diff --git a/transform.js b/transform.js
index ef743a3b1..7cd105a41 100644
--- a/transform.js
+++ b/transform.js
@@ -1,7 +1,6 @@
 import arrayEach from './_arrayEach.js';
 import baseCreate from './_baseCreate.js';
 import baseForOwn from './_baseForOwn.js';
-import baseIteratee from './_baseIteratee.js';
 import getPrototype from './_getPrototype.js';
 import isArray from './isArray.js';
 import isBuffer from './isBuffer.js';
@@ -23,7 +22,7 @@ import isTypedArray from './isTypedArray.js';
  * @since 1.3.0
  * @category Object
  * @param {Object} object The object to iterate over.
- * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {Function} iteratee The function invoked per iteration.
  * @param {*} [accumulator] The custom accumulator value.
  * @returns {*} Returns the accumulated value.
  * @example
@@ -43,7 +42,6 @@ function transform(object, iteratee, accumulator) {
   const isArr = isArray(object);
   const isArrLike = isArr || isBuffer(object) || isTypedArray(object);
 
-  iteratee = baseIteratee(iteratee, 4);
   if (accumulator == null) {
     const Ctor = object && object.constructor;
     if (isArrLike) {
diff --git a/unionBy.js b/unionBy.js
index 9e0491c99..6b7061468 100644
--- a/unionBy.js
+++ b/unionBy.js
@@ -1,5 +1,4 @@
 import baseFlatten from './_baseFlatten.js';
-import baseIteratee from './_baseIteratee.js';
 import baseUniq from './_baseUniq.js';
 import isArrayLikeObject from './isArrayLikeObject.js';
 import last from './last.js';
@@ -16,23 +15,19 @@ import last from './last.js';
  * @since 4.0.0
  * @category Array
  * @param {...Array} [arrays] The arrays to inspect.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {Array} Returns the new array of combined values.
  * @example
  *
  * _.unionBy([2.1], [1.2, 2.3], Math.floor);
  * // => [2.1, 1.2]
- *
- * // The `_.property` iteratee shorthand.
- * _.unionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
- * // => [{ 'x': 1 }, { 'x': 2 }]
  */
 function unionBy(...arrays) {
   let iteratee = last(arrays);
   if (isArrayLikeObject(iteratee)) {
     iteratee = undefined;
   }
-  return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), baseIteratee(iteratee, 2));
+  return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), iteratee);
 }
 
 export default unionBy;
diff --git a/uniqBy.js b/uniqBy.js
index e08603d24..fa59a364a 100644
--- a/uniqBy.js
+++ b/uniqBy.js
@@ -1,4 +1,3 @@
-import baseIteratee from './_baseIteratee.js';
 import baseUniq from './_baseUniq.js';
 
 /**
@@ -13,19 +12,15 @@ import baseUniq from './_baseUniq.js';
  * @since 4.0.0
  * @category Array
  * @param {Array} array The array to inspect.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {Array} Returns the new duplicate free array.
  * @example
  *
  * _.uniqBy([2.1, 1.2, 2.3], Math.floor);
  * // => [2.1, 1.2]
- *
- * // The `_.property` iteratee shorthand.
- * _.uniqBy([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
- * // => [{ 'x': 1 }, { 'x': 2 }]
  */
 function uniqBy(array, iteratee) {
-  return (array && array.length) ? baseUniq(array, baseIteratee(iteratee, 2)) : [];
+  return (array && array.length) ? baseUniq(array, iteratee) : [];
 }
 
 export default uniqBy;
diff --git a/unzipWith.js b/unzipWith.js
index a4b83a8c3..2c7b68cef 100644
--- a/unzipWith.js
+++ b/unzipWith.js
@@ -12,7 +12,7 @@ import unzip from './unzip.js';
  * @since 3.8.0
  * @category Array
  * @param {Array} array The array of grouped elements to process.
- * @param {Function} [iteratee=_.identity] The function to combine
+ * @param {Function} iteratee The function to combine
  *  regrouped values.
  * @returns {Array} Returns the new array of regrouped elements.
  * @example
@@ -28,9 +28,6 @@ function unzipWith(array, iteratee) {
     return [];
   }
   const result = unzip(array);
-  if (iteratee == null) {
-    return result;
-  }
   return arrayMap(result, group => apply(iteratee, undefined, group));
 }
 
diff --git a/update.js b/update.js
index c4b10036b..68005e87b 100644
--- a/update.js
+++ b/update.js
@@ -1,5 +1,4 @@
 import baseUpdate from './_baseUpdate.js';
-import castFunction from './_castFunction.js';
 
 /**
  * This method is like `_.set` except that accepts `updater` to produce the
@@ -29,7 +28,7 @@ import castFunction from './_castFunction.js';
  * // => 0
  */
 function update(object, path, updater) {
-  return object == null ? object : baseUpdate(object, path, castFunction(updater));
+  return object == null ? object : baseUpdate(object, path, updater);
 }
 
 export default update;
diff --git a/updateWith.js b/updateWith.js
index 190b092b8..2cb4e9517 100644
--- a/updateWith.js
+++ b/updateWith.js
@@ -1,5 +1,4 @@
 import baseUpdate from './_baseUpdate.js';
-import castFunction from './_castFunction.js';
 
 /**
  * This method is like `_.update` except that it accepts `customizer` which is
@@ -27,7 +26,7 @@ import castFunction from './_castFunction.js';
  */
 function updateWith(object, path, updater, customizer) {
   customizer = typeof customizer == 'function' ? customizer : undefined;
-  return object == null ? object : baseUpdate(object, path, castFunction(updater), customizer);
+  return object == null ? object : baseUpdate(object, path, updater, customizer);
 }
 
 export default updateWith;
diff --git a/xorBy.js b/xorBy.js
index 32ca346a5..e9d67787f 100644
--- a/xorBy.js
+++ b/xorBy.js
@@ -1,5 +1,4 @@
 import arrayFilter from './_arrayFilter.js';
-import baseIteratee from './_baseIteratee.js';
 import baseXor from './_baseXor.js';
 import isArrayLikeObject from './isArrayLikeObject.js';
 import last from './last.js';
@@ -16,23 +15,19 @@ import last from './last.js';
  * @since 4.0.0
  * @category Array
  * @param {...Array} [arrays] The arrays to inspect.
- * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @param {Function} iteratee The iteratee invoked per element.
  * @returns {Array} Returns the new array of filtered values.
  * @example
  *
  * _.xorBy([2.1, 1.2], [2.3, 3.4], Math.floor);
  * // => [1.2, 3.4]
- *
- * // The `_.property` iteratee shorthand.
- * _.xorBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
- * // => [{ 'x': 2 }]
  */
 function xorBy(...arrays) {
   let iteratee = last(arrays);
   if (isArrayLikeObject(iteratee)) {
     iteratee = undefined;
   }
-  return baseXor(arrayFilter(arrays, isArrayLikeObject), baseIteratee(iteratee, 2));
+  return baseXor(arrayFilter(arrays, isArrayLikeObject), iteratee);
 }
 
 export default xorBy;
diff --git a/zipWith.js b/zipWith.js
index 581294405..72de687c9 100644
--- a/zipWith.js
+++ b/zipWith.js
@@ -10,7 +10,7 @@ import unzipWith from './unzipWith.js';
  * @since 3.8.0
  * @category Array
  * @param {...Array} [arrays] The arrays to process.
- * @param {Function} [iteratee=_.identity] The function to combine
+ * @param {Function} iteratee The function to combine
  *  grouped values.
  * @returns {Array} Returns the new array of grouped elements.
  * @example
@@ -23,7 +23,6 @@ import unzipWith from './unzipWith.js';
 function zipWith(...arrays) {
   const length = arrays.length;
   let iteratee = length > 1 ? arrays[length - 1] : undefined;
-
   iteratee = typeof iteratee == 'function' ? (arrays.pop(), iteratee) : undefined;
   return unzipWith(arrays, iteratee);
 }