Cleanup _.spread docs & tests.

lodash.src.js

@@ -7580,39 +7580,42 @@
     }
 
     /**
-     * Creates a function accepting an array as argument, that invokes `func`
-     * with arguments taken from this array, like `Function#apply`.
-     * This works obviously well with `Promise.all`.
+     * Creates a function that invokes `func` with the `this` binding of `thisArg`
+     * and the array of arguments provided to the created function much like
+     * [Function#apply](http://es5.github.io/#x15.3.4.3).
      *
      * @static
      * @memberOf _
      * @category Function
-     * @param {Function} The function to alter.
+     * @param {Function} The function to spread arguments over.
      * @param {*} [thisArg] The `this` binding of `func`.
      * @returns {*} Returns the new function.
      * @example
      *
-     * var spread = _.spread(function (who, what) {
+     * var spread = _.spread(function(who, what) {
      *   return who + ' says ' + what;
      * });
      *
-     * spread(['John', 'hello']) // => 'John says hello'
+     * spread(['Fred', 'hello']);
+     * // => 'Fred says hello'
      *
-     * // With Promise
+     * // with a Promise
      * var numbers = Promise.all([
-     *   Promise.resolve(42),
-     *   Promise.resolve(33)
-     * ])
+     *   Promise.resolve(40),
+     *   Promise.resolve(36)
+     * ]);
      *
-     * numbers.then(_.spread(function (a, b) { return a + b })) // Promise of 75
-     * // instead of...
-     * numbers.then(function (nums) { return nums[0] + nums[1] })
+     * var add = function(x, y) {
+     *   return x + y;
+     * };
+     *
+     * numbers.then(_.spread(add));
+     * // => a Promise of 76
      */
-    function spread (func, thisArg) {
-      if (typeof func !== 'function') {
+    function spread(func, thisArg) {
+      if (typeof func != 'function') {
         throw new TypeError(FUNC_ERROR_TEXT);
       }
-
       return function(array) {
         return func.apply(thisArg, array);
       };

test/test.js

@@ -12243,45 +12243,36 @@
   QUnit.module('lodash.spread');
 
   (function() {
-    function Pair(x, y) {
-      this.x = x;
-      this.y = y;
-
-      return 42;
+    function add(x, y) {
+      return x + y;
     }
 
-    function divide(n, d) {
-      return n / d;
-    }
-
-    test('should pass arguments to `func`', 1, function() {
-      var spread = _.spread(divide);
-      strictEqual(spread([4, 2]), 2);
+    test('should spread arguments to `func`', 1, function() {
+      var spread = _.spread(add);
+      strictEqual(spread([4, 2]), 6);
     });
 
-    test('should fail when receiving non-array argument', 1, function() {
-      var spread = _.spread(divide);
-      var err;
-      try {
-        spread(4, 2);
-      } catch (e) {
-        err = e;
-      }
-      strictEqual(_.isError(err), true);
+    test('should throw a TypeError when receiving a non-array `array` argument', 1, function() {
+      raises(function() { _.spread(4, 2); }, TypeError);
     });
 
-    test('should dynamically `func` to `thisArg`', 2, function() {
-      var self = {z: 3};
-      var spread = _.spread(Pair, self);
-      var result = spread([1, 2]);
-      strictEqual(result, 42);
-      deepEqual(self, {x: 1, y: 2, z: 3});
+    test('should provide the correct `func` arguments', 1, function() {
+      var args;
+
+      var spread = _.spread(function() {
+        args = slice.call(arguments);
+      });
+
+      spread([4, 2], 'ignored');
+      deepEqual(args, [4, 2]);
     });
 
-    test('should use `undefined` for extra values', 1, function() {
-      var self = {};
-      _.spread(Pair, self)([1]);
-      deepEqual(self, {x: 1, y: undefined});
+    test('should support the `thisArg` argument', 1, function() {
+      var spread = _.spread(function(x, y) {
+        return this[x] + this[y];
+      }, [4, 2]);
+
+      strictEqual(spread([0, 1]), 6);
     });
   }());