feat: allow to provide a list of transport implementations

This commit adds the ability to provide a list of transport
implementations to use when connecting to an Engine.IO server.

This can be used to use HTTP long-polling based on `fetch()`, instead
of the default implementation based on the `XMLHttpRequest` object.

```
import { Socket, Fetch, WebSocket } from "engine.io-client";

const socket = new Socket({
  transports: [Fetch, WebSocket]
});
```

This is useful in some environments that do not provide a
`XMLHttpRequest` object, like Chrome extension background scripts.

> XMLHttpRequest() can't be called from a service worker, extension or
otherwise. Replace calls from your background script to
XMLHttpRequest() with calls to global fetch().

Source: https://developer.chrome.com/docs/extensions/develop/migrate/to-service-workers#replace-xmlhttprequest

Related:

- #716
- socketio/socket.io#4980

This is also useful when running the client with Deno or Bun, as it
allows to use the built-in `fetch()` method and `WebSocket` object,
instead of using the `xmlhttprequest-ssl` and `ws` Node.js packages.

Related: socketio/socket.io-deno#12

This feature also comes with the ability to exclude the code related to
unused transports (a.k.a. "tree-shaking"):

```js
import { SocketWithoutUpgrade, WebSocket } from "engine.io-client";

const socket = new SocketWithoutUpgrade({
  transports: [WebSocket]
});
```

In that case, the code related to HTTP long-polling and WebTransport
will be excluded from the final bundle.

Related: socketio/socket.io#4393

lib/transports/xmlhttprequest.ts → lib/globals.node.ts

@@ -1,6 +1,6 @@
-import * as XMLHttpRequestModule from "xmlhttprequest-ssl";
-
-export const XHR = XMLHttpRequestModule.default || XMLHttpRequestModule;
+export const nextTick = process.nextTick;
+export const globalThisShim = global;
+export const defaultBinaryType = "nodebuffer";
 
 export function createCookieJar() {
   return new CookieJar();

lib/transports/websocket-constructor.browser.ts → lib/globals.ts

@@ -1,5 +1,3 @@
-import { globalThisShim as globalThis } from "../globalThis.js";
-
 export const nextTick = (() => {
   const isPromiseAvailable =
     typeof Promise === "function" && typeof Promise.resolve === "function";
@@ -10,6 +8,16 @@ export const nextTick = (() => {
   }
 })();
 
-export const WebSocket = globalThis.WebSocket || globalThis.MozWebSocket;
-export const usingBrowserWebSocket = true;
+export const globalThisShim = (() => {
+  if (typeof self !== "undefined") {
+    return self;
+  } else if (typeof window !== "undefined") {
+    return window;
+  } else {
+    return Function("return this")();
+  }
+})();
+
 export const defaultBinaryType = "arraybuffer";
+
+export function createCookieJar() {}

lib/index.ts

@@ -1,13 +1,21 @@
 import { Socket } from "./socket.js";
 
 export { Socket };
-export { SocketOptions } from "./socket.js";
+export {
+  SocketOptions,
+  SocketWithoutUpgrade,
+  SocketWithUpgrade,
+} from "./socket.js";
 export const protocol = Socket.protocol;
 export { Transport, TransportError } from "./transport.js";
 export { transports } from "./transports/index.js";
 export { installTimerFunctions } from "./util.js";
 export { parse } from "./contrib/parseuri.js";
-export { nextTick } from "./transports/websocket-constructor.js";
+export { nextTick } from "./globals.node.js";
 
 export { Fetch } from "./transports/polling-fetch.js";
+export { XHR as NodeXHR } from "./transports/polling-xhr.node.js";
 export { XHR } from "./transports/polling-xhr.js";
+export { WS as NodeWebSocket } from "./transports/websocket.node.js";
+export { WS as WebSocket } from "./transports/websocket.js";
+export { WT as WebTransport } from "./transports/webtransport.js";