feat: Implement EventSource

examples/eventsource.js

@@ -0,0 +1,17 @@
+'use strict'
+
+const { EventSource } = require('../')
+
+async function main () {
+  const ev = new EventSource('https://smee.io/wcGp009TievZCLT')
+  ev.onmessage = (event) => {
+    console.log(event)
+  }
+  ev.onerror = event => {
+    console.log(event)
+  }
+  ev.onopen = event => {
+    console.log(event)
+  }
+}
+main()

index.js

@@ -149,3 +149,7 @@ module.exports.MockClient = MockClient
 module.exports.MockPool = MockPool
 module.exports.MockAgent = MockAgent
 module.exports.mockErrors = mockErrors
+
+const { EventSource } = require('./lib/eventsource/eventsource')
+
+module.exports.EventSource = EventSource

lib/eventsource/constants.js

@@ -0,0 +1,93 @@
+'use strict'
+
+/**
+ * A reconnection time, in milliseconds. This must initially be an implementation-defined value,
+ * probably in the region of a few seconds.
+ *
+ * In Comparison:
+ * - Chrome uses 3000ms.
+ * - Deno uses 5000ms.
+ */
+const defaultReconnectionTime = 3000
+
+/**
+ * The readyState attribute represents the state of the connection.
+ * @enum
+ * @readonly
+ * @see https://html.spec.whatwg.org/multipage/server-sent-events.html#dom-eventsource-readystate-dev
+ */
+
+/**
+ * The connection has not yet been established, or it was closed and the user
+ * agent is reconnecting.
+ * @type {0}
+ */
+const CONNECTING = 0
+
+/**
+ * The user agent has an open connection and is dispatching events as it
+ * receives them.
+ * @type {1}
+ */
+const OPEN = 1
+
+/**
+ * The connection is not open, and the user agent is not trying to reconnect.
+ * @type {2}
+ */
+const CLOSED = 2
+
+/**
+ * Requests for the element will have their mode set to "cors" and their credentials mode set to "same-origin".
+ * @type {'anonymous'}
+ */
+const ANONYMOUS = 'anonymous'
+
+/**
+ * Requests for the element will have their mode set to "cors" and their credentials mode set to "include".
+ * @type {'use-credentials'}
+ */
+const USE_CREDENTIALS = 'use-credentials'
+
+/**
+ * @type {number[]} BOM
+ */
+const BOM = [0xEF, 0xBB, 0xBF]
+/**
+ * @type {10} LF
+ */
+const LF = 0x0A
+/**
+ * @type {13} CR
+ */
+const CR = 0x0D
+/**
+ * @type {58} COLON
+ */
+const COLON = 0x3A
+/**
+ * @type {32} SPACE
+ */
+const SPACE = 0x20
+
+const validMessageEventFieldNames = [
+  'data',
+  'event',
+  'id',
+  'retry'
+]
+
+module.exports = {
+  defaultReconnectionTime,
+  CONNECTING,
+  OPEN,
+  CLOSED,
+  BOM,
+  LF,
+  CR,
+  COLON,
+  SPACE,
+  validMessageEventFieldNames,
+  ANONYMOUS,
+  USE_CREDENTIALS
+}