diff --git a/test/js/samples/legacy-default/expected-bundle.js b/test/js/samples/legacy-default/expected-bundle.js
index 3804eeb7df..f2fa173262 100644
--- a/test/js/samples/legacy-default/expected-bundle.js
+++ b/test/js/samples/legacy-default/expected-bundle.js
@@ -61,8 +61,8 @@ function destroy(detach) {
 	this._fragment = this._state = null;
 }
 
-function differs(a, b) {
-	return a !== b || ((a && typeof a === 'object') || typeof a === 'function');
+function _differs(a, b) {
+	return a != a ? b == b : a !== b || ((a && typeof a === 'object') || typeof a === 'function');
 }
 
 function dispatchObservers(component, group, changed, newState, oldState) {
@@ -161,7 +161,7 @@ function _set(newState) {
 		dirty = false;
 
 	for (var key in newState) {
-		if (differs(newState[key], oldState[key])) changed[key] = dirty = true;
+		if (this._differs(newState[key], oldState[key])) changed[key] = dirty = true;
 	}
 	if (!dirty) return;
 
@@ -199,7 +199,8 @@ var proto = {
 	_recompute: noop,
 	_set: _set,
 	_mount: _mount,
-	_unmount: _unmount
+	_unmount: _unmount,
+	_differs: _differs
 };
 
 /* generated by Svelte vX.Y.Z */