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',

lib/internal/process/pre_execution.js

@@ -298,6 +298,7 @@ function setupWarningHandler() {
   }
 }
 
+// https://html.spec.whatwg.org/multipage/server-sent-events.html
 // https://fetch.spec.whatwg.org/
 // https://websockets.spec.whatwg.org/
 function setupUndici() {
@@ -328,6 +329,12 @@ function setupUndici() {
     };
   }
 
+  if (getOptionValue('--experimental-eventsource')) {
+    ObjectDefineProperties(globalThis, {
+      EventSource: lazyInterface('EventSource'),
+    });
+  }
+
   if (!getOptionValue('--no-experimental-fetch')) {
     // Fetch is meant to return a Promise, but not be async.
     function fetch(input, init = undefined) {

src/node_options.cc

@@ -376,6 +376,11 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
             &EnvironmentOptions::enable_source_maps,
             kAllowedInEnvvar);
   AddOption("--experimental-abortcontroller", "", NoOp{}, kAllowedInEnvvar);
+  AddOption("--experimental-eventsource",
+            "experimental EventSource API",
+            &EnvironmentOptions::experimental_eventsource,
+            kAllowedInEnvvar,
+            true);
   AddOption("--experimental-fetch",
             "experimental Fetch API",
             &EnvironmentOptions::experimental_fetch,

src/node_options.h

@@ -107,6 +107,7 @@ class EnvironmentOptions : public Options {
   bool detect_module = false;
   std::string dns_result_order;
   bool enable_source_maps = false;
+  bool experimental_eventsource = false;
   bool experimental_fetch = true;
   bool experimental_websocket = false;
   bool experimental_global_customevent = true;

test/common/globals.js

@@ -124,6 +124,7 @@ const webIdlExposedWindow = new Set([
   'Request',
   'Response',
   'WebSocket',
+  'EventSource',
 ]);
 
 const nodeGlobals = new Set([

test/common/index.js

@@ -373,6 +373,10 @@ if (global.WebSocket) {
   knownGlobals.push(WebSocket);
 }
 
+if (global.EventSource) {
+  knownGlobals.push(EventSource);
+}
+
 function allowGlobals(...allowlist) {
   knownGlobals = knownGlobals.concat(allowlist);
 }

test/parallel/test-eventsource.js

@@ -0,0 +1,7 @@
+// Flags: --experimental-eventsource
+'use strict';
+
+require('../common');
+const assert = require('assert');
+
+assert.strictEqual(typeof EventSource, 'function');