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

node_modules/engine.io/build/transports/polling-jsonp.js

@@ -0,0 +1,54 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.JSONP = void 0;
+const polling_1 = require("./polling");
+const qs = require("querystring");
+const rDoubleSlashes = /\\\\n/g;
+const rSlashes = /(\\)?\\n/g;
+class JSONP extends polling_1.Polling {
+    /**
+     * JSON-P polling transport.
+     *
+     * @api public
+     */
+    constructor(req) {
+        super(req);
+        this.head = "___eio[" + (req._query.j || "").replace(/[^0-9]/g, "") + "](";
+        this.foot = ");";
+    }
+    /**
+     * Handles incoming data.
+     * Due to a bug in \n handling by browsers, we expect a escaped string.
+     *
+     * @api private
+     */
+    onData(data) {
+        // we leverage the qs module so that we get built-in DoS protection
+        // and the fast alternative to decodeURIComponent
+        data = qs.parse(data).d;
+        if ("string" === typeof data) {
+            // client will send already escaped newlines as \\\\n and newlines as \\n
+            // \\n must be replaced with \n and \\\\n with \\n
+            data = data.replace(rSlashes, function (match, slashes) {
+                return slashes ? match : "\n";
+            });
+            super.onData(data.replace(rDoubleSlashes, "\\n"));
+        }
+    }
+    /**
+     * Performs the write.
+     *
+     * @api private
+     */
+    doWrite(data, options, callback) {
+        // we must output valid javascript, not valid json
+        // see: http://timelessrepo.com/json-isnt-a-javascript-subset
+        const js = JSON.stringify(data)
+            .replace(/\u2028/g, "\\u2028")
+            .replace(/\u2029/g, "\\u2029");
+        // prepare response
+        data = this.head + js + this.foot;
+        super.doWrite(data, options, callback);
+    }
+}
+exports.JSONP = JSONP;