diff --git a/.internal/baseKeys.js b/.internal/baseKeys.js
deleted file mode 100644
index 04ff372bc..000000000
--- a/.internal/baseKeys.js
+++ /dev/null
@@ -1,27 +0,0 @@
-import isPrototype from './isPrototype.js'
-
-/** Used to check objects for own properties. */
-const hasOwnProperty = Object.prototype.hasOwnProperty
-
-/**
- * The base implementation of `keys` which doesn't treat sparse arrays as dense.
- *
- * @private
- * @param {Object} object The object to query.
- * @returns {Array} Returns the array of property names.
- */
-function baseKeys(object) {
-  object = Object(object)
-  if (!isPrototype(object)) {
-    return Object.keys(object)
-  }
-  const result = []
-  for (const key in object) {
-    if (hasOwnProperty.call(object, key) && key != 'constructor') {
-      result.push(key)
-    }
-  }
-  return result
-}
-
-export default baseKeys
diff --git a/.internal/baseKeysIn.js b/.internal/baseKeysIn.js
deleted file mode 100644
index 60bc2f210..000000000
--- a/.internal/baseKeysIn.js
+++ /dev/null
@@ -1,34 +0,0 @@
-import isObject from '../isObject.js'
-import isPrototype from './isPrototype.js'
-
-/** Used to check objects for own properties. */
-const hasOwnProperty = Object.prototype.hasOwnProperty
-
-/**
- * The base implementation of `keysIn` which doesn't treat sparse arrays as dense.
- *
- * @private
- * @param {Object} object The object to query.
- * @returns {Array} Returns the array of property names.
- */
-function baseKeysIn(object) {
-  const result = []
-  if (object == null) {
-    return result
-  }
-  if (!isObject(object)) {
-    for (const key in Object(object)) {
-      result.push(key)
-    }
-    return result
-  }
-  const isProto = isPrototype(object)
-  for (const key in object) {
-    if (!(key == 'constructor' && (isProto || !hasOwnProperty.call(object, key)))) {
-      result.push(key)
-    }
-  }
-  return result
-}
-
-export default baseKeysIn
diff --git a/.internal/getAllKeysIn.js b/.internal/getAllKeysIn.js
index 84c30a4e4..c9714e131 100644
--- a/.internal/getAllKeysIn.js
+++ b/.internal/getAllKeysIn.js
@@ -1,5 +1,4 @@
 import getSymbolsIn from './getSymbolsIn.js'
-import baseKeysIn from './baseKeysIn.js'
 
 /**
  * Creates an array of own and inherited enumerable property names and symbols of `object`.
@@ -9,7 +8,10 @@ import baseKeysIn from './baseKeysIn.js'
  * @returns {Array} Returns the array of property names and symbols.
  */
 function getAllKeysIn(object) {
-  const result = baseKeysIn(object)
+  const result = []
+  for (const key in object) {
+    result.push(key)
+  }
   if (!Array.isArray(object)) {
     result.push(...getSymbolsIn(object))
   }
diff --git a/defaults.js b/defaults.js
index eb552bd68..99e234dbd 100644
--- a/defaults.js
+++ b/defaults.js
@@ -1,5 +1,4 @@
 import eq from './eq.js'
-import baseKeysIn from './.internal/baseKeysIn.js'
 
 /** Used for built-in method references. */
 const objectProto = Object.prototype
@@ -28,22 +27,18 @@ const hasOwnProperty = objectProto.hasOwnProperty
  */
 function defaults(object, ...sources) {
   object = Object(object)
-  let srcIndex = -1
-  const srcLength = sources.length
-  while (++srcIndex < srcLength) {
-    const source = sources[srcIndex]
-    const props = baseKeysIn(source)
-    let propsIndex = -1
-    const propsLength = props.length
-    while (++propsIndex < propsLength) {
-      const key = props[propsIndex]
-      const value = object[key]
-      if (value === undefined ||
-           (eq(value, objectProto[key]) && !hasOwnProperty.call(object, key))) {
-        object[key] = source[key]
+  sources.forEach((source) => {
+    if (source != null) {
+      source = Object(source)
+      for (const key in source) {
+        const value = object[key]
+        if (value === undefined ||
+            (eq(value, objectProto[key]) && !hasOwnProperty.call(object, key))) {
+          object[key] = source[key]
+        }
       }
     }
-  }
+  })
   return object
 }
 
diff --git a/isEmpty.js b/isEmpty.js
index 6b5d82499..9876cc38d 100644
--- a/isEmpty.js
+++ b/isEmpty.js
@@ -1,4 +1,3 @@
-import baseKeys from './.internal/baseKeys.js'
 import getTag from './.internal/getTag.js'
 import isArguments from './isArguments.js'
 import isArrayLike from './isArrayLike.js'
@@ -54,7 +53,7 @@ function isEmpty(value) {
     return !value.size
   }
   if (isPrototype(value)) {
-    return !baseKeys(value).length
+    return !Object.keys(value).length
   }
   for (const key in value) {
     if (hasOwnProperty.call(value, key)) {
diff --git a/keys.js b/keys.js
index 0af002410..43b241c11 100644
--- a/keys.js
+++ b/keys.js
@@ -1,5 +1,4 @@
 import arrayLikeKeys from './.internal/arrayLikeKeys.js'
-import baseKeys from './.internal/baseKeys.js'
 import isArrayLike from './isArrayLike.js'
 
 /**
@@ -30,7 +29,9 @@ import isArrayLike from './isArrayLike.js'
  * // => ['0', '1']
  */
 function keys(object) {
-  return isArrayLike(object) ? arrayLikeKeys(object) : baseKeys(object)
+  return isArrayLike(object)
+    ? arrayLikeKeys(object)
+    : Object.keys(Object(object))
 }
 
 export default keys
diff --git a/size.js b/size.js
index 5b2c40ef4..831011e56 100644
--- a/size.js
+++ b/size.js
@@ -1,4 +1,3 @@
-import baseKeys from './.internal/baseKeys.js'
 import getTag from './.internal/getTag.js'
 import isArrayLike from './isArrayLike.js'
 import isString from './isString.js'
@@ -38,7 +37,7 @@ function size(collection) {
   if (tag == mapTag || tag == setTag) {
     return collection.size
   }
-  return baseKeys(collection).length
+  return Object.keys(collection).length
 }
 
 export default size