diff --git a/packages/react/src/ReactChildren.js b/packages/react/src/ReactChildren.js
index 5068c87d00..3d4d3e19e7 100644
--- a/packages/react/src/ReactChildren.js
+++ b/packages/react/src/ReactChildren.js
@@ -36,7 +36,7 @@ var SUBSEPARATOR = ':';
  * @param {string} key to be escaped.
  * @return {string} the escaped key.
  */
-function escape(key: string): string {
+function escape(key) {
   var escapeRegex = /[=:]/g;
   var escaperLookup = {
     '=': '=0',