From bc2e821ccc65f32b56b0ec4a0e195433c84b09aa Mon Sep 17 00:00:00 2001
From: Benjamin Gruenbaum <benjamingr@gmail.com>
Date: Thu, 28 May 2020 16:52:52 +0300
Subject: [PATCH] events: deal with no argument case
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PR-URL: https://github.com/nodejs/node/pull/33611
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
---
 lib/internal/event_target.js      |  4 ++++
 test/parallel/test-eventtarget.js | 13 +++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/lib/internal/event_target.js b/lib/internal/event_target.js
index 5ece72ea1d9433..47f7b1d592a1c7 100644
--- a/lib/internal/event_target.js
+++ b/lib/internal/event_target.js
@@ -15,6 +15,7 @@ const {
     ERR_INVALID_ARG_TYPE,
     ERR_EVENT_RECURSION,
     ERR_OUT_OF_RANGE,
+    ERR_MISSING_ARGS
   }
 } = require('internal/errors');
 
@@ -45,6 +46,9 @@ class Event {
 
 
   constructor(type, options) {
+    if (arguments.length === 0) {
+      throw new ERR_MISSING_ARGS('type');
+    }
     if (options != null && typeof options !== 'object')
       throw new ERR_INVALID_ARG_TYPE('options', 'object', options);
     const { cancelable, bubbles, composed } = { ...options };
diff --git a/test/parallel/test-eventtarget.js b/test/parallel/test-eventtarget.js
index c0e760d13b1369..cf52030aee5a05 100644
--- a/test/parallel/test-eventtarget.js
+++ b/test/parallel/test-eventtarget.js
@@ -29,6 +29,7 @@ ok(EventTarget);
   strictEqual(ev.defaultPrevented, false);
   strictEqual(typeof ev.timeStamp, 'number');
 
+  // Compatibility properties with the DOM
   deepStrictEqual(ev.composedPath(), []);
   strictEqual(ev.returnValue, true);
   strictEqual(ev.bubbles, false);
@@ -59,7 +60,15 @@ ok(EventTarget);
   ev.cancelBubble = 'some-truthy-value';
   strictEqual(ev.cancelBubble, true);
 }
-
+{
+  // No argument behavior - throw TypeError
+  throws(() => {
+    new Event();
+  }, TypeError);
+  // Too many arguments passed behavior - ignore additional arguments
+  const ev = new Event('foo', {}, {});
+  strictEqual(ev.type, 'foo');
+}
 {
   const ev = new Event('foo', { cancelable: true });
   strictEqual(ev.type, 'foo');
@@ -419,6 +428,6 @@ ok(EventTarget);
 {
   const target = new EventTarget();
   strictEqual(target.toString(), '[object EventTarget]');
-  const event = new Event();
+  const event = new Event('');
   strictEqual(event.toString(), '[object Event]');
 }