Add Event web API (#1059)

1 files changed, 66 insertions, 0 deletions

diff --git a/js/event_target_test.ts b/js/event_target_test.ts
new file mode 100644
index 000000000..ebb92c7f0
--- /dev/null
+++ b/js/event_target_test.ts
@@ -0,0 +1,66 @@
+// Copyright 2018 the Deno authors. All rights reserved. MIT license.
+import { test, assert, assertEqual } from "./test_util.ts";
+
+test(function addEventListenerTest() {
+  const document = new EventTarget();
+
+  assertEqual(document.addEventListener("x", null, false), undefined);
+  assertEqual(document.addEventListener("x", null, true), undefined);
+  assertEqual(document.addEventListener("x", null), undefined);
+});
+
+test(function constructedEventTargetCanBeUsedAsExpected() {
+  const target = new EventTarget();
+  const event = new Event("foo", { bubbles: true, cancelable: false });
+  let callCount = 0;
+
+  function listener(e) {
+    assertEqual(e, event);
+    ++callCount;
+  }
+
+  target.addEventListener("foo", listener);
+
+  target.dispatchEvent(event);
+  assertEqual(callCount, 1);
+
+  target.dispatchEvent(event);
+  assertEqual(callCount, 2);
+
+  target.removeEventListener("foo", listener);
+  target.dispatchEvent(event);
+  assertEqual(callCount, 2);
+});
+
+test(function anEventTargetCanBeSubclassed() {
+  class NicerEventTarget extends EventTarget {
+    on(type, listener?, options?) {
+      this.addEventListener(type, listener, options);
+    }
+
+    off(type, callback?, options?) {
+      this.removeEventListener(type, callback, options);
+    }
+  }
+
+  const target = new NicerEventTarget();
+  const event = new Event("foo", { bubbles: true, cancelable: false });
+  let callCount = 0;
+
+  function listener() {
+    ++callCount;
+  }
+
+  target.on("foo", listener);
+  assertEqual(callCount, 0);
+
+  target.off("foo", listener);
+  assertEqual(callCount, 0);
+});
+
+test(function removingNullEventListenerShouldSucceed() {
+  const document = new EventTarget();
+  assertEqual(document.removeEventListener("x", null, false), undefined);
+  assertEqual(document.removeEventListener("x", null, true), undefined);
+  assertEqual(document.removeEventListener("x", null), undefined);
+});