1 files changed, 32 insertions, 0 deletions
diff --git a/build-es/waterfall.js b/build-es/waterfall.js
new file mode 100644
index 0000000..c629bcf
--- /dev/null
+++ b/build-es/waterfall.js
@@ -0,0 +1,32 @@
+'use strict';
+
+import isArray from 'lodash-es/isArray';
+import noop from 'lodash-es/noop';
+import once from 'lodash-es/once';
+import rest from 'lodash-es/rest';
+
+import ensureAsync from './ensureAsync';
+import iterator from './iterator';
+
+export default  function(tasks, cb) {
+    cb = once(cb || noop);
+    if (!isArray(tasks)) return cb(new Error('First argument to waterfall must be an array of functions'));
+    if (!tasks.length) return cb();
+
+    function wrapIterator(iterator) {
+        return rest(function(err, args) {
+            if (err) {
+                cb.apply(null, [err].concat(args));
+            } else {
+                var next = iterator.next();
+                if (next) {
+                    args.push(wrapIterator(next));
+                } else {
+                    args.push(cb);
+                }
+                ensureAsync(iterator).apply(null, args);
+            }
+        });
+    }
+    wrapIterator(iterator(tasks))();
+}