added unit testing, and started implementing unit tests...phew

node_modules/async/apply.js

@@ -0,0 +1,68 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+    value: true
+});
+
+exports.default = function (fn /*, ...args*/) {
+    var args = (0, _slice2.default)(arguments, 1);
+    return function () /*callArgs*/{
+        var callArgs = (0, _slice2.default)(arguments);
+        return fn.apply(null, args.concat(callArgs));
+    };
+};
+
+var _slice = require('./internal/slice');
+
+var _slice2 = _interopRequireDefault(_slice);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+;
+
+/**
+ * Creates a continuation function with some arguments already applied.
+ *
+ * Useful as a shorthand when combined with other control flow functions. Any
+ * arguments passed to the returned function are added to the arguments
+ * originally passed to apply.
+ *
+ * @name apply
+ * @static
+ * @memberOf module:Utils
+ * @method
+ * @category Util
+ * @param {Function} fn - The function you want to eventually apply all
+ * arguments to. Invokes with (arguments...).
+ * @param {...*} arguments... - Any number of arguments to automatically apply
+ * when the continuation is called.
+ * @returns {Function} the partially-applied function
+ * @example
+ *
+ * // using apply
+ * async.parallel([
+ *     async.apply(fs.writeFile, 'testfile1', 'test1'),
+ *     async.apply(fs.writeFile, 'testfile2', 'test2')
+ * ]);
+ *
+ *
+ * // the same process without using apply
+ * async.parallel([
+ *     function(callback) {
+ *         fs.writeFile('testfile1', 'test1', callback);
+ *     },
+ *     function(callback) {
+ *         fs.writeFile('testfile2', 'test2', callback);
+ *     }
+ * ]);
+ *
+ * // It's possible to pass any number of additional arguments when calling the
+ * // continuation:
+ *
+ * node> var fn = async.apply(sys.puts, 'one');
+ * node> fn('two', 'three');
+ * one
+ * two
+ * three
+ */
+module.exports = exports['default'];