diff --git a/lib/FrameManager.js b/lib/FrameManager.js
index 031fc71d..26e5179f 100644
--- a/lib/FrameManager.js
+++ b/lib/FrameManager.js
@@ -977,7 +977,7 @@ class WaitTask {
     this._frame = frame;
     this._polling = polling;
     this._timeout = timeout;
-    this._predicateBody = helper.isString(predicateBody) ? 'return ' + predicateBody : 'return (' + predicateBody + ')(...args)';
+    this._predicateBody = helper.isString(predicateBody) ? 'return (' + predicateBody + ')' : 'return (' + predicateBody + ')(...args)';
     this._args = args;
     this._runCount = 0;
     frame._waitTasks.add(this);