Init. Map does not function and only working on backend at the moment.

node_modules/engine.io/build/transports/websocket.js

@@ -0,0 +1,121 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.WebSocket = void 0;
+const transport_1 = require("../transport");
+const debug_1 = require("debug");
+const debug = (0, debug_1.default)("engine:ws");
+class WebSocket extends transport_1.Transport {
+    /**
+     * WebSocket transport
+     *
+     * @param {http.IncomingMessage}
+     * @api public
+     */
+    constructor(req) {
+        super(req);
+        this.socket = req.websocket;
+        this.socket.on("message", (data, isBinary) => {
+            const message = isBinary ? data : data.toString();
+            debug('received "%s"', message);
+            super.onData(message);
+        });
+        this.socket.once("close", this.onClose.bind(this));
+        this.socket.on("error", this.onError.bind(this));
+        this.writable = true;
+        this.perMessageDeflate = null;
+    }
+    /**
+     * Transport name
+     *
+     * @api public
+     */
+    get name() {
+        return "websocket";
+    }
+    /**
+     * Advertise upgrade support.
+     *
+     * @api public
+     */
+    get handlesUpgrades() {
+        return true;
+    }
+    /**
+     * Advertise framing support.
+     *
+     * @api public
+     */
+    get supportsFraming() {
+        return true;
+    }
+    /**
+     * Writes a packet payload.
+     *
+     * @param {Array} packets
+     * @api private
+     */
+    send(packets) {
+        this.writable = false;
+        for (let i = 0; i < packets.length; i++) {
+            const packet = packets[i];
+            const isLast = i + 1 === packets.length;
+            // always creates a new object since ws modifies it
+            const opts = {};
+            if (packet.options) {
+                opts.compress = packet.options.compress;
+            }
+            const onSent = (err) => {
+                if (err) {
+                    return this.onError("write error", err.stack);
+                }
+                else if (isLast) {
+                    this.writable = true;
+                    this.emit("drain");
+                }
+            };
+            const send = (data) => {
+                if (this.perMessageDeflate) {
+                    const len = "string" === typeof data ? Buffer.byteLength(data) : data.length;
+                    if (len < this.perMessageDeflate.threshold) {
+                        opts.compress = false;
+                    }
+                }
+                debug('writing "%s"', data);
+                this.socket.send(data, opts, onSent);
+            };
+            if (packet.options && typeof packet.options.wsPreEncoded === "string") {
+                send(packet.options.wsPreEncoded);
+            }
+            else if (this._canSendPreEncodedFrame(packet)) {
+                // the WebSocket frame was computed with WebSocket.Sender.frame()
+                // see https://github.com/websockets/ws/issues/617#issuecomment-283002469
+                this.socket._sender.sendFrame(packet.options.wsPreEncodedFrame, onSent);
+            }
+            else {
+                this.parser.encodePacket(packet, this.supportsBinary, send);
+            }
+        }
+    }
+    /**
+     * Whether the encoding of the WebSocket frame can be skipped.
+     * @param packet
+     * @private
+     */
+    _canSendPreEncodedFrame(packet) {
+        var _a, _b, _c;
+        return (!this.perMessageDeflate &&
+            typeof ((_b = (_a = this.socket) === null || _a === void 0 ? void 0 : _a._sender) === null || _b === void 0 ? void 0 : _b.sendFrame) === "function" &&
+            ((_c = packet.options) === null || _c === void 0 ? void 0 : _c.wsPreEncodedFrame) !== undefined);
+    }
+    /**
+     * Closes the transport.
+     *
+     * @api private
+     */
+    doClose(fn) {
+        debug("closing");
+        this.socket.close();
+        fn && fn();
+    }
+}
+exports.WebSocket = WebSocket;