Add _.zipWith.

lodash.src.js

@@ -6061,6 +6061,28 @@
       return result;
     }
 
+    /**
+     * Combines elements of given arrays, like `_.zip` but with a function
+     * specifying how they should be combined.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] Arrays to be zipped with accumulator.
+     * @param {Function} accumulator Function used to reduce zipped elements.
+     * @returns {Array} Returns new array of accumulated groups.
+     * @example
+     *
+     * _.zipWith([1, 2, 3], [10, 20 , 30], _.add);
+     * // => [11, 22, 33]
+     */
+    var zipWith = restParam(function(arrays) {
+      var iteratee = arrays.pop();
+      return arrayMap(unzip(arrays), function(array) {
+        return arrayReduce(array, iteratee, undefined, true);
+      });
+    });
+
     /*------------------------------------------------------------------------*/
 
     /**
@@ -12009,6 +12031,7 @@
     lodash.xor = xor;
     lodash.zip = zip;
     lodash.zipObject = zipObject;
+    lodash.zipWith = zipWith;
 
     // Add aliases.
     lodash.backflow = flowRight;

test/test.js

@@ -16718,6 +16718,20 @@
 
   /*--------------------------------------------------------------------------*/
 
+  QUnit.module('lodash.zipWith');
+
+  (function() {
+    test('should combine values in lists with given function', 2, function() {
+      var array1 = [1, 2, 3],
+          array2 = [1, 2, 3];
+
+      deepEqual(_.zipWith(array1, array2, _.add), [2, 4, 6]);
+      deepEqual(_.zipWith(array1, [], _.add), [1, 2, 3]);
+    });
+  }())
+
+  /*--------------------------------------------------------------------------*/
+
   QUnit.module('lodash(...).commit');
 
   (function() {
@@ -17516,7 +17530,7 @@
 
     var acceptFalsey = _.difference(allMethods, rejectFalsey);
 
-    test('should accept falsey arguments', 218, function() {
+    test('should accept falsey arguments', 219, function() {
       var emptyArrays = _.map(falsey, _.constant([])),
           isExposed = '_' in root,
           oldDash = root._;