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

node_modules/async/concat.js

@@ -0,0 +1,43 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+
+var _doLimit = require('./internal/doLimit');
+
+var _doLimit2 = _interopRequireDefault(_doLimit);
+
+var _concatLimit = require('./concatLimit');
+
+var _concatLimit2 = _interopRequireDefault(_concatLimit);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+/**
+ * Applies `iteratee` to each item in `coll`, concatenating the results. Returns
+ * the concatenated list. The `iteratee`s are called in parallel, and the
+ * results are concatenated as they return. There is no guarantee that the
+ * results array will be returned in the original order of `coll` passed to the
+ * `iteratee` function.
+ *
+ * @name concat
+ * @static
+ * @memberOf module:Collections
+ * @method
+ * @category Collection
+ * @param {Array|Iterable|Object} coll - A collection to iterate over.
+ * @param {AsyncFunction} iteratee - A function to apply to each item in `coll`,
+ * which should use an array as its result. Invoked with (item, callback).
+ * @param {Function} [callback(err)] - A callback which is called after all the
+ * `iteratee` functions have finished, or an error occurs. Results is an array
+ * containing the concatenated results of the `iteratee` function. Invoked with
+ * (err, results).
+ * @example
+ *
+ * async.concat(['dir1','dir2','dir3'], fs.readdir, function(err, files) {
+ *     // files is now a list of filenames that exist in the 3 directories
+ * });
+ */
+exports.default = (0, _doLimit2.default)(_concatLimit2.default, Infinity);
+module.exports = exports['default'];