Add performance.now (#1633)

1 files changed, 10 insertions, 0 deletions

diff --git a/js/performance_test.ts b/js/performance_test.ts
new file mode 100644
index 000000000..154dadbbe
--- /dev/null
+++ b/js/performance_test.ts
@@ -0,0 +1,10 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { test, assert } from "./test_util.ts";
+
+test(function now() {
+  const start = performance.now();
+  setTimeout(() => {
+    const end = performance.now();
+    assert(end - start >= 10);
+  }, 10);
+});