awaitable series (lol)

lib/series.js

@@ -1,4 +1,4 @@
-import parallel from './internal/parallel';
+import _parallel from './internal/parallel';
 import eachOfSeries from './eachOfSeries';
 
 /**
@@ -34,6 +34,7 @@ import eachOfSeries from './eachOfSeries';
  * functions have completed. This function gets a results array (or object)
  * containing all the result arguments passed to the `task` callbacks. Invoked
  * with (err, result).
+ * @return {Promise} a promise, if no callback is passed
  * @example
  * async.series([
  *     function(callback) {
@@ -66,5 +67,5 @@ import eachOfSeries from './eachOfSeries';
  * });
  */
 export default function series(tasks, callback) {
-    parallel(eachOfSeries, tasks, callback);
+    return _parallel(eachOfSeries, tasks, callback);
 }

test/es2017/awaitableFunctions.js

@@ -484,6 +484,17 @@ module.exports = function () {
         ], 2)
         expect(calls).to.eql([1, 1, 1, 1])
     });
+    it('should return a Promise: series', async () => {
+        expect (async.series.name).to.contain('series')
+        const calls = []
+        await async.series([
+            async () => { await Promise.resolve(); calls.push(1) },
+            async () => { await Promise.resolve(); calls.push(1) },
+            async () => { await Promise.resolve(); calls.push(1) },
+            async () => { await Promise.resolve(); calls.push(1) },
+        ], 2)
+        expect(calls).to.eql([1, 1, 1, 1])
+    });
 
     it('should return a Promise: race', async () => {
         expect (async.race.name).to.contain('race')