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

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

@@ -0,0 +1,25 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const polling_1 = require("./polling");
+const polling_jsonp_1 = require("./polling-jsonp");
+const websocket_1 = require("./websocket");
+const webtransport_1 = require("./webtransport");
+exports.default = {
+    polling: polling,
+    websocket: websocket_1.WebSocket,
+    webtransport: webtransport_1.WebTransport,
+};
+/**
+ * Polling polymorphic constructor.
+ *
+ * @api private
+ */
+function polling(req) {
+    if ("string" === typeof req._query.j) {
+        return new polling_jsonp_1.JSONP(req);
+    }
+    else {
+        return new polling_1.Polling(req);
+    }
+}
+polling.upgradesTo = ["websocket", "webtransport"];