diff --git a/.internal/MapCache.js b/.internal/MapCache.js
index 62206dd63..926d390be 100644
--- a/.internal/MapCache.js
+++ b/.internal/MapCache.js
@@ -1,17 +1,45 @@
-import mapCacheClear from './.internal/mapCacheClear.js';
-import mapCacheDelete from './.internal/mapCacheDelete.js';
-import mapCacheGet from './.internal/mapCacheGet.js';
-import mapCacheHas from './.internal/mapCacheHas.js';
-import mapCacheSet from './.internal/mapCacheSet.js';
+
+import Hash from './.internal/Hash.js';
+import ListCache from './.internal/ListCache.js';
 
 /**
- * Creates a map cache object to store key-value pairs.
+ * Gets the data for `map`.
  *
  * @private
- * @constructor
- * @param {Array} [entries] The key-value pairs to cache.
+ * @param {Object} map The map to query.
+ * @param {string} key The reference key.
+ * @returns {*} Returns the map data.
  */
+function getMapData({ __data__ }, key) {
+  const data = __data__;
+  return isKeyable(key)
+    ? data[typeof key == 'string' ? 'string' : 'hash']
+    : data.map;
+}
+
+/**
+ * Checks if `value` is suitable for use as unique object key.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is suitable, else `false`.
+ */
+function isKeyable(value) {
+  const type = typeof value;
+  return (type == 'string' || type == 'number' || type == 'symbol' || type == 'boolean')
+    ? (value !== '__proto__')
+    : (value === null);
+}
+
 class MapCache {
+
+  /**
+   * Creates a map cache object to store key-value pairs.
+   *
+   * @private
+   * @constructor
+   * @param {Array} [entries] The key-value pairs to cache.
+   */
   constructor(entries) {
     let index = -1;
     const length = entries == null ? 0 : entries.length;
@@ -22,13 +50,72 @@ class MapCache {
       this.set(entry[0], entry[1]);
     }
   }
+
+  /**
+   * Removes all key-value entries from the map.
+   *
+   * @memberOf MapCache
+   */
+  clear() {
+    this.size = 0;
+    this.__data__ = {
+      'hash': new Hash,
+      'map': new (Map || ListCache),
+      'string': new Hash
+    };
+  }
+
+  /**
+   * Removes `key` and its value from the map.
+   *
+   * @memberOf MapCache
+   * @param {string} key The key of the value to remove.
+   * @returns {boolean} Returns `true` if the entry was removed, else `false`.
+   */
+  delete(key) {
+    const result = getMapData(this, key)['delete'](key);
+    this.size -= result ? 1 : 0;
+    return result;
+  }
+
+  /**
+   * Gets the map value for `key`.
+   *
+   * @memberOf MapCache
+   * @param {string} key The key of the value to get.
+   * @returns {*} Returns the entry value.
+   */
+  get(key) {
+    return getMapData(this, key).get(key);
+  }
+
+  /**
+   * Checks if a map value for `key` exists.
+   *
+   * @memberOf MapCache
+   * @param {string} key The key of the entry to check.
+   * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+   */
+  has(key) {
+    return getMapData(this, key).has(key);
+  }
+
+  /**
+   * Sets the map `key` to `value`.
+   *
+   * @memberOf MapCache
+   * @param {string} key The key of the value to set.
+   * @param {*} value The value to set.
+   * @returns {Object} Returns the map cache instance.
+   */
+  set(key, value) {
+    const data = getMapData(this, key);
+    const size = data.size;
+
+    data.set(key, value);
+    this.size += data.size == size ? 0 : 1;
+    return this;
+  }
 }
 
-// Add methods to `MapCache`.
-MapCache.prototype.clear = mapCacheClear;
-MapCache.prototype['delete'] = mapCacheDelete;
-MapCache.prototype.get = mapCacheGet;
-MapCache.prototype.has = mapCacheHas;
-MapCache.prototype.set = mapCacheSet;
-
 export default MapCache;
diff --git a/.internal/getMapData.js b/.internal/getMapData.js
deleted file mode 100644
index d15ea4614..000000000
--- a/.internal/getMapData.js
+++ /dev/null
@@ -1,18 +0,0 @@
-import isKeyable from './.internal/isKeyable.js';
-
-/**
- * Gets the data for `map`.
- *
- * @private
- * @param {Object} map The map to query.
- * @param {string} key The reference key.
- * @returns {*} Returns the map data.
- */
-function getMapData({ __data__ }, key) {
-  const data = __data__;
-  return isKeyable(key)
-    ? data[typeof key == 'string' ? 'string' : 'hash']
-    : data.map;
-}
-
-export default getMapData;
diff --git a/.internal/isKeyable.js b/.internal/isKeyable.js
deleted file mode 100644
index 0931e86ef..000000000
--- a/.internal/isKeyable.js
+++ /dev/null
@@ -1,15 +0,0 @@
-/**
- * Checks if `value` is suitable for use as unique object key.
- *
- * @private
- * @param {*} value The value to check.
- * @returns {boolean} Returns `true` if `value` is suitable, else `false`.
- */
-function isKeyable(value) {
-  const type = typeof value;
-  return (type == 'string' || type == 'number' || type == 'symbol' || type == 'boolean')
-    ? (value !== '__proto__')
-    : (value === null);
-}
-
-export default isKeyable;
diff --git a/.internal/mapCacheClear.js b/.internal/mapCacheClear.js
deleted file mode 100644
index e0be01516..000000000
--- a/.internal/mapCacheClear.js
+++ /dev/null
@@ -1,20 +0,0 @@
-import Hash from './.internal/Hash.js';
-import ListCache from './.internal/ListCache.js';
-
-/**
- * Removes all key-value entries from the map.
- *
- * @private
- * @name clear
- * @memberOf MapCache
- */
-function mapCacheClear() {
-  this.size = 0;
-  this.__data__ = {
-    'hash': new Hash,
-    'map': new (Map || ListCache),
-    'string': new Hash
-  };
-}
-
-export default mapCacheClear;
diff --git a/.internal/mapCacheDelete.js b/.internal/mapCacheDelete.js
deleted file mode 100644
index 924f15305..000000000
--- a/.internal/mapCacheDelete.js
+++ /dev/null
@@ -1,18 +0,0 @@
-import getMapData from './.internal/getMapData.js';
-
-/**
- * Removes `key` and its value from the map.
- *
- * @private
- * @name delete
- * @memberOf MapCache
- * @param {string} key The key of the value to remove.
- * @returns {boolean} Returns `true` if the entry was removed, else `false`.
- */
-function mapCacheDelete(key) {
-  const result = getMapData(this, key)['delete'](key);
-  this.size -= result ? 1 : 0;
-  return result;
-}
-
-export default mapCacheDelete;
diff --git a/.internal/mapCacheGet.js b/.internal/mapCacheGet.js
deleted file mode 100644
index daa9058b3..000000000
--- a/.internal/mapCacheGet.js
+++ /dev/null
@@ -1,16 +0,0 @@
-import getMapData from './.internal/getMapData.js';
-
-/**
- * Gets the map value for `key`.
- *
- * @private
- * @name get
- * @memberOf MapCache
- * @param {string} key The key of the value to get.
- * @returns {*} Returns the entry value.
- */
-function mapCacheGet(key) {
-  return getMapData(this, key).get(key);
-}
-
-export default mapCacheGet;
diff --git a/.internal/mapCacheHas.js b/.internal/mapCacheHas.js
deleted file mode 100644
index 49707bdde..000000000
--- a/.internal/mapCacheHas.js
+++ /dev/null
@@ -1,16 +0,0 @@
-import getMapData from './.internal/getMapData.js';
-
-/**
- * Checks if a map value for `key` exists.
- *
- * @private
- * @name has
- * @memberOf MapCache
- * @param {string} key The key of the entry to check.
- * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
- */
-function mapCacheHas(key) {
-  return getMapData(this, key).has(key);
-}
-
-export default mapCacheHas;
diff --git a/.internal/mapCacheSet.js b/.internal/mapCacheSet.js
deleted file mode 100644
index a86bef00e..000000000
--- a/.internal/mapCacheSet.js
+++ /dev/null
@@ -1,22 +0,0 @@
-import getMapData from './.internal/getMapData.js';
-
-/**
- * Sets the map `key` to `value`.
- *
- * @private
- * @name set
- * @memberOf MapCache
- * @param {string} key The key of the value to set.
- * @param {*} value The value to set.
- * @returns {Object} Returns the map cache instance.
- */
-function mapCacheSet(key, value) {
-  const data = getMapData(this, key);
-  const size = data.size;
-
-  data.set(key, value);
-  this.size += data.size == size ? 0 : 1;
-  return this;
-}
-
-export default mapCacheSet;