Consolidate aggregate modules.

.internal/arrayAggregator.js

@@ -1,22 +0,0 @@
-/**
- * A specialized version of `baseAggregator` for arrays.
- *
- * @private
- * @param {Array} [array] The array to iterate over.
- * @param {Function} setter The function to set `accumulator` values.
- * @param {Function} iteratee The iteratee to transform keys.
- * @param {Object} accumulator The initial aggregated object.
- * @returns {Function} Returns `accumulator`.
- */
-function arrayAggregator(array, setter, iteratee, accumulator) {
-  let index = -1;
-  const length = array == null ? 0 : array.length;
-
-  while (++index < length) {
-    const value = array[index];
-    setter(accumulator, value, iteratee(value), array);
-  }
-  return accumulator;
-}
-
-export default arrayAggregator;

.internal/baseAggregator.js

@@ -1,21 +0,0 @@
-import baseEach from './baseEach.js';
-
-/**
- * Aggregates elements of `collection` on `accumulator` with keys transformed
- * by `iteratee` and values set by `setter`.
- *
- * @private
- * @param {Array|Object} collection The collection to iterate over.
- * @param {Function} setter The function to set `accumulator` values.
- * @param {Function} iteratee The iteratee to transform keys.
- * @param {Object} accumulator The initial aggregated object.
- * @returns {Function} Returns `accumulator`.
- */
-function baseAggregator(collection, setter, iteratee, accumulator) {
-  baseEach(collection, (value, key, collection) => {
-    setter(accumulator, value, iteratee(value), collection);
-  });
-  return accumulator;
-}
-
-export default baseAggregator;

.internal/createAggregator.js

@@ -1,20 +0,0 @@
-import arrayAggregator from './.internal/arrayAggregator.js';
-import baseAggregator from './.internal/baseAggregator.js';
-
-/**
- * Creates a function like `groupBy`.
- *
- * @private
- * @param {Function} setter The function to set accumulator values.
- * @param {Function} [initializer] The accumulator object initializer.
- * @returns {Function} Returns the new aggregator function.
- */
-function createAggregator(setter, initializer) {
-  return (collection, iteratee) => {
-    const func = Array.isArray(collection) ? arrayAggregator : baseAggregator;
-    const accumulator = initializer ? initializer() : {};
-    return func(collection, setter, iteratee, accumulator);
-  };
-}
-
-export default createAggregator;

countBy.js

@@ -1,5 +1,5 @@
 import baseAssignValue from './.internal/baseAssignValue.js';
-import createAggregator from './.internal/createAggregator.js';
+import reduce from './reduce.js';
 
 /** Used to check objects for own properties. */
 const hasOwnProperty = Object.prototype.hasOwnProperty;
@@ -20,12 +20,15 @@ const hasOwnProperty = Object.prototype.hasOwnProperty;
  * countBy([6.1, 4.2, 6.3], Math.floor);
  * // => { '4': 1, '6': 2 }
  */
-const countBy = createAggregator((result, value, key) => {
-  if (hasOwnProperty.call(result, key)) {
-    ++result[key];
-  } else {
-    baseAssignValue(result, key, 1);
-  }
-});
+function countBy(collection, iteratee) {
+  return reduce(collection, (result, value, key) => {
+    if (hasOwnProperty.call(result, key)) {
+      ++result[key];
+    } else {
+      baseAssignValue(result, key, 1);
+    }
+    return result;
+  }, {});
+}
 
 export default countBy;

groupBy.js

@@ -1,5 +1,5 @@
 import baseAssignValue from './.internal/baseAssignValue.js';
-import createAggregator from './.internal/createAggregator.js';
+import reduce from './reduce.js';
 
 /** Used to check objects for own properties. */
 const hasOwnProperty = Object.prototype.hasOwnProperty;
@@ -21,12 +21,15 @@ const hasOwnProperty = Object.prototype.hasOwnProperty;
  * groupBy([6.1, 4.2, 6.3], Math.floor);
  * // => { '4': [4.2], '6': [6.1, 6.3] }
  */
-const groupBy = createAggregator((result, value, key) => {
-  if (hasOwnProperty.call(result, key)) {
-    result[key].push(value);
-  } else {
-    baseAssignValue(result, key, [value]);
-  }
-});
+function groupBy(collection, iteratee) {
+  return reduce(collection, (result, value, key) => {
+    if (hasOwnProperty.call(result, key)) {
+      result[key].push(value);
+    } else {
+      baseAssignValue(result, key, [value]);
+    }
+    return result;
+  }, {});
+}
 
 export default groupBy;

keyBy.js

@@ -1,5 +1,5 @@
 import baseAssignValue from './.internal/baseAssignValue.js';
-import createAggregator from './.internal/createAggregator.js';
+import reduce from './reduce.js';
 
 /**
  * Creates an object composed of keys generated from the results of running
@@ -19,16 +19,13 @@ import createAggregator from './.internal/createAggregator.js';
  *   { 'dir': 'right', 'code': 100 }
  * ];
  *
- * keyBy(array, function(o) {
- *   return String.fromCharCode(o.code);
- * });
+ * keyBy(array, ({ code }) => String.fromCharCode(code));
  * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
- *
- * keyBy(array, 'dir');
- * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }
  */
-const keyBy = createAggregator((result, value, key) => {
-  baseAssignValue(result, key, value);
-});
+function keyBy(collection, iteratee) {
+  return reduce(collection, (result, value, key) => (
+    baseAssignValue(result, key, value)
+  ), {});
+}
 
 export default keyBy;

partition.js

@@ -1,4 +1,4 @@
-import createAggregator from './.internal/createAggregator.js';
+import reduce from './reduce.js';
 
 /**
  * Creates an array of elements split into two groups, the first of which
@@ -19,10 +19,13 @@ import createAggregator from './.internal/createAggregator.js';
  *   { 'user': 'pebbles', 'age': 1,  'active': false }
  * ];
  *
- * partition(users, o => o.active);
+ * partition(users, ({ active }) => active);
  * // => objects for [['fred'], ['barney', 'pebbles']]
  */
-const partition = createAggregator((result, value, key) =>
-  result[key ? 0 : 1].push(value), () => [[], []]);
+function partition(collection, predicate) {
+  return reduce(collection, (result, value, key) => (
+    result[key ? 0 : 1].push(value)
+  ), [[], []]);
+}
 
 export default partition;