Bump to v4.2.0.

flatMap.js

@@ -1,18 +1,17 @@
-var arrayMap = require('./_arrayMap'),
-    baseFlatten = require('./_baseFlatten'),
-    baseIteratee = require('./_baseIteratee');
+var baseFlatten = require('./_baseFlatten'),
+    map = require('./map');
 
 /**
- * Creates an array of flattened values by running each element in `array`
+ * Creates an array of flattened values by running each element in `collection`
  * through `iteratee` and concating its result to the other mapped values.
- * The iteratee is invoked with three arguments: (value, index|key, array).
+ * The iteratee is invoked with three arguments: (value, index|key, collection).
  *
  * @static
  * @memberOf _
- * @category Array
- * @param {Array} array The array to iterate over.
+ * @category Collection
+ * @param {Array|Object} collection The collection to iterate over.
  * @param {Function|Object|string} [iteratee=_.identity] The function invoked per iteration.
- * @returns {Array} Returns the new array.
+ * @returns {Array} Returns the new flattened array.
  * @example
  *
  * function duplicate(n) {
@@ -22,9 +21,8 @@ var arrayMap = require('./_arrayMap'),
  * _.flatMap([1, 2], duplicate);
  * // => [1, 1, 2, 2]
  */
-function flatMap(array, iteratee) {
-  var length = array ? array.length : 0;
-  return length ? baseFlatten(arrayMap(array, baseIteratee(iteratee, 3))) : [];
+function flatMap(collection, iteratee) {
+  return baseFlatten(map(collection, iteratee));
 }
 
 module.exports = flatMap;