diff --git a/build.js b/build.js
index <HASH>..<HASH> 100644
--- a/build.js
+++ b/build.js
@@ -1,3 +1,4 @@
+"use strict";
 var stealTools = require("steal-tools");
 
 stealTools.export({
diff --git a/can-stache-ast.js b/can-stache-ast.js
index <HASH>..<HASH> 100644
--- a/can-stache-ast.js
+++ b/can-stache-ast.js
@@ -1,3 +1,4 @@
+"use strict";
 var controls = require("./controls");
 var parser = require('can-view-parser');
 
diff --git a/controls.js b/controls.js
index <HASH>..<HASH> 100644
--- a/controls.js
+++ b/controls.js
@@ -1,3 +1,4 @@
+"use strict";
 var mustacheLineBreakRegExp = /(?:(^|\r?\n)(\s*)(\{\{([\s\S]*)\}\}\}?)([^\S\n\r]*)($|\r?\n))|(\{\{([\s\S]*)\}\}\}?)/g,
 	mustacheWhitespaceRegExp = /(\s*)(\{\{\{?)(-?)([\s\S]*?)(-?)(\}\}\}?)(\s*)/g;
Adds use strict. Fixes canjs/canjs#<I>