feat: implement EventSource

.eslintrc.js

@@ -341,6 +341,7 @@ module.exports = {
     Crypto: 'readable',
     CryptoKey: 'readable',
     DecompressionStream: 'readable',
+    EventSource: 'readable',
     fetch: 'readable',
     FormData: 'readable',
     navigator: 'readable',

benchmark/events_source/message-event-instantiate.js

@@ -0,0 +1,21 @@
+'use strict';
+
+const common = require('../common.js');
+
+const bench = common.createBenchmark(main, {
+  n: [100000],
+}, {
+  flags: ['--expose-internals'],
+});
+
+function main({ n }) {
+  const { MessageEvent } = require('internal/event_source');
+
+  bench.start();
+
+  for (let i = 0; i < n; i++) {
+    new MessageEvent('message', { });
+  }
+
+  bench.end(n);
+}

lib/internal/bootstrap/web/exposed-window-or-worker.js

@@ -55,3 +55,7 @@ defineReplaceableLazyAttribute(globalThis, 'perf_hooks', ['performance']);
 // https://w3c.github.io/FileAPI/#creating-revoking
 const { installObjectURLMethods } = require('internal/url');
 installObjectURLMethods();
+
+// https://html.spec.whatwg.org/multipage/server-sent-events.html#dom-eventsource-readystate-dev
+exposeLazyInterfaces(globalThis, 'internal/event_source', ['EventSource']);
+defineReplaceableLazyAttribute(globalThis, 'internal/event_source', ['EventSource'], false);