1 files changed, 3 insertions, 0 deletions
diff --git a/lib/reduce.js b/lib/reduce.js
index 8145db7..4718631 100644
--- a/lib/reduce.js
+++ b/lib/reduce.js
@@ -1,4 +1,6 @@
 import eachOfSeries from './eachOfSeries';
+import noop from 'lodash/noop';
+import once from './internal/once';
 
 /**
  * Reduces `coll` into a single value using an async `iteratee` to return each
@@ -41,6 +43,7 @@ import eachOfSeries from './eachOfSeries';
  * });
  */
 export default function reduce(coll, memo, iteratee, callback) {
+    callback = once(callback || noop);
     eachOfSeries(coll, function(x, i, callback) {
         iteratee(memo, x, function(err, v) {
             memo = v;