refactor: remove JSONP polling

JSONP polling was only used in IE7/8, which are not supported anymore.

BREAKING CHANGE: the jsonp and forceJSONP options are removed.

Author: darrachequesne

README.md

@@ -226,13 +226,6 @@ Exposed as `eio` in the browser standalone build.
       - `agent` (`http.Agent`): `http.Agent` to use, defaults to `false` (NodeJS only)
       - `upgrade` (`Boolean`): defaults to true, whether the client should try
       to upgrade the transport from long-polling to something better.
-      - `forceJSONP` (`Boolean`): forces JSONP for polling transport.
-      - `jsonp` (`Boolean`): determines whether to use JSONP when
-        necessary for polling. If disabled (by settings to false) an error will
-        be emitted (saying "No transports available") if no other transports
-        are available. If another transport is available for opening a
-        connection (e.g. WebSocket) that transport
-        will be used instead.
       - `forceBase64` (`Boolean`): forces base 64 encoding for polling transport even when XHR2 responseType is available and WebSocket even if the used standard supports binary.
       - `enablesXDR` (`Boolean`): enables XDomainRequest for IE8 to avoid loading bar flashing with click sound. default to `false` because XDomainRequest has a flaw of not sending cookie.
       - `withCredentials` (`Boolean`): defaults to `false`, whether to include credentials (cookies, authorization headers, TLS client certificates, etc.) with cross-origin XHR polling requests.

lib/socket.ts

@@ -46,21 +46,6 @@ export interface SocketOptions {
    */
   upgrade: boolean;
 
-  /**
-   * Forces JSONP for polling transport.
-   */
-  forceJSONP: boolean;
-
-  /**
-   * Determines whether to use JSONP when necessary for polling. If
-   * disabled (by settings to false) an error will be emitted (saying
-   * "No transports available") if no other transports are available.
-   * If another transport is available for opening a connection (e.g.
-   * WebSocket) that transport will be used instead.
-   * @default true
-   */
-  jsonp: boolean;
-
   /**
    * Forces base 64 encoding for polling transport even when XHR2
    * responseType is available and WebSocket even if the used standard
@@ -322,7 +307,6 @@ export class Socket extends Emitter {
         agent: false,
         withCredentials: false,
         upgrade: true,
-        jsonp: true,
         timestampParam: "t",
         rememberUpgrade: false,
         rejectUnauthorized: true,

lib/transports/index.ts

@@ -1,49 +1,7 @@
-import * as XMLHttpRequestModule from "xmlhttprequest-ssl";
 import { XHR } from "./polling-xhr.js";
-import { JSONP } from "./polling-jsonp.js";
 import { WS } from "./websocket.js";
 
-const XMLHttpRequest = XMLHttpRequestModule.default || XMLHttpRequestModule;
-
-/**
- * Polling transport polymorphic constructor.
- * Decides on xhr vs jsonp based on feature detection.
- *
- * @api private
- */
-
-function polling(opts) {
-  let xhr;
-  let xd = false;
-  let xs = false;
-  const jsonp = false !== opts.jsonp;
-
-  if (typeof location !== "undefined") {
-    const isSSL = "https:" === location.protocol;
-    let port = location.port;
-
-    // some user agents have empty `location.port`
-    if (!port) {
-      port = isSSL ? "443" : "80";
-    }
-
-    xd = opts.hostname !== location.hostname || port !== opts.port;
-    xs = opts.secure !== isSSL;
-  }
-
-  opts.xdomain = xd;
-  opts.xscheme = xs;
-  xhr = new XMLHttpRequest(opts);
-
-  if ("open" in xhr && !opts.forceJSONP) {
-    return new XHR(opts);
-  } else {
-    if (!jsonp) throw new Error("JSONP disabled");
-    return new JSONP(opts);
-  }
-}
-
 export const transports = {
   websocket: WS,
-  polling
+  polling: XHR
 };

lib/transports/polling-jsonp.ts

@@ -91,33 +91,7 @@ describe("connection", function() {
     });
   }
 
-  it("should not connect at all when JSONP forced and disabled", done => {
-    const socket = new Socket({
-      transports: ["polling"],
-      forceJSONP: true,
-      jsonp: false
-    });
-    socket.on("error", msg => {
-      expect(msg).to.be("No transports available");
-      done();
-    });
-  });
-
   if (env.wsSupport && !env.isOldSimulator && !env.isAndroid && !env.isIE11) {
-    it("should connect with ws when JSONP forced and disabled", done => {
-      const socket = new Socket({
-        transports: ["polling", "websocket"],
-        forceJSONP: true,
-        jsonp: false
-      });
-
-      socket.on("open", () => {
-        expect(socket.transport.name).to.be("websocket");
-        socket.close();
-        done();
-      });
-    });
-
     it("should defer close when upgrading", done => {
       const socket = new Socket();
       socket.on("open", () => {