diff --git a/stream/map.js b/stream/map.js
index 4d1a8b2f..5ba9457c 100644
--- a/stream/map.js
+++ b/stream/map.js
@@ -1,3 +1,5 @@
+"use strict"
+
 module.exports = function(object, callback) {
 	return object["fantasy-land/map"](callback)
 }
\ No newline at end of file