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

node_modules/async/concatSeries.js

@@ -0,0 +1,36 @@
+'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 }; }
+
+/**
+ * The same as [`concat`]{@link module:Collections.concat} but runs only a single async operation at a time.
+ *
+ * @name concatSeries
+ * @static
+ * @memberOf module:Collections
+ * @method
+ * @see [async.concat]{@link module:Collections.concat}
+ * @category Collection
+ * @param {Array|Iterable|Object} coll - A collection to iterate over.
+ * @param {AsyncFunction} iteratee - A function to apply to each item in `coll`.
+ * The iteratee should complete with an array an array of results.
+ * 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).
+ */
+exports.default = (0, _doLimit2.default)(_concatLimit2.default, 1);
+module.exports = exports['default'];