ES6-ify codebase (#1553)

* cancelable foreach

* cancelable waterfall

* cancellable auto

* fix lint

* fix tests

* cancelable whilst/until/during/forever

* fix waterfall test.  It WILL get there

* docs

* use rest params instead of slice

* clean up internals

* remove property func

* clarify uses of createTester

* happy path async funtions in asyncify

* stop using arguments

* DLL to class

* moar arrows

* fix merge issues

* remove forOwn

* moar arrows

* fix merge mistake

* even more arrows, what can stop him

* mo more fn.apply(null,...)

* remove more spurious uses of apply

* update lint config

* just when you thought there couldn't possibly be more arrows

* use eslint:recommended

* even less uses or aguments

* get rid of prototype cuteness

* fix concat tests

* fix more tests

1 files changed, 6 insertions, 9 deletions

diff --git a/lib/ensureAsync.js b/lib/ensureAsync.js
index a579efc..b2b35b9 100644
--- a/lib/ensureAsync.js
+++ b/lib/ensureAsync.js
@@ -1,5 +1,4 @@
 import setImmediate from './internal/setImmediate';
-import initialParams from './internal/initialParams';
 import { isAsync } from './internal/wrapAsync';
 
 /**
@@ -39,19 +38,17 @@ import { isAsync } from './internal/wrapAsync';
  */
 export default function ensureAsync(fn) {
     if (isAsync(fn)) return fn;
-    return initialParams(function (args, callback) {
+    return function (...args/*, callback*/) {
+        var callback = args.pop()
         var sync = true;
-        args.push(function () {
-            var innerArgs = arguments;
+        args.push((...innerArgs) => {
             if (sync) {
-                setImmediate(function () {
-                    callback.apply(null, innerArgs);
-                });
+                setImmediate(() => callback(...innerArgs));
             } else {
-                callback.apply(null, innerArgs);
+                callback(...innerArgs);
             }
         });
         fn.apply(this, args);
         sync = false;
-    });
+    };
 }