diff --git a/lib/coffee_script/nodes.js b/lib/coffee_script/nodes.js
index e19dd48d..401de91d 100644
--- a/lib/coffee_script/nodes.js
+++ b/lib/coffee_script/nodes.js
@@ -964,7 +964,7 @@
     ASSIGNMENT: ['||=', '&&=', '?='],
     PREFIX_OPERATORS: ['typeof', 'delete'],
     constructor: function constructor(operator, first, second, flip) {
-      this.children = [(this.first = first), (this.second = second)];
+      this.children = compact([(this.first = first), (this.second = second)]);
       this.operator = this.CONVERSIONS[operator] || operator;
       this.flip = !!flip;
       return this;
diff --git a/src/nodes.coffee b/src/nodes.coffee
index e00c2452..82424be7 100644
--- a/src/nodes.coffee
+++ b/src/nodes.coffee
@@ -754,7 +754,7 @@ OpNode: exports.OpNode: inherit Node, {
   PREFIX_OPERATORS: ['typeof', 'delete']
 
   constructor: (operator, first, second, flip) ->
-    @children: [@first: first, @second: second]
+    @children: compact [@first: first, @second: second]
     @operator: @CONVERSIONS[operator] or operator
     @flip: !!flip
     this