Update

lib/negotiate.ts

@@ -0,0 +1,102 @@
+import debugModule from "debug"; // debug()
+import { SocketOptions } from "./socket.js";
+import { encode } from "./contrib/parseqs.js";
+
+const debug = debugModule("engine.io-client:negotiate"); // debug()
+
+class NegotiateError extends Error {
+  public readonly type = "NegotiateError";
+
+  constructor(
+    reason: string,
+    readonly context: any
+  ) {
+    super(reason);
+  }
+}
+
+export interface NegotiateResult {
+  url: string;
+  token: string;
+}
+
+export class Negotiate {
+  public query: Record<string, string>;
+  protected opts: SocketOptions;
+  protected setTimeoutFn: typeof setTimeout;
+
+  /**
+   * Transport abstract constructor.
+   *
+   * @param {Object} opts - options
+   * @protected
+   */
+  constructor(opts) {
+    this.opts = opts;
+    this.query = opts.query;
+  }
+
+  /**
+   * Start the negotiation
+   */
+  public async start(): Promise<NegotiateResult> {
+    const uri = this.uri();
+    let negotiateResult = await fetch(uri);
+
+    if (negotiateResult.status !== 200) {
+      throw new NegotiateError("Unexpected status code " + negotiateResult.status, negotiateResult);
+    }
+
+    const result = await negotiateResult.json();
+    if (!result.url) {
+      throw new NegotiateError("Missing property `url` in negotiate response.", result);
+    }
+
+    return result;
+  }
+
+  /**
+   * Generates uri for negotiate.
+   *
+   * @private
+   */
+  private uri() {
+    const schema = this.opts.secure ? "https" : "http";
+    const query: { b64?: number; sid?: string } = this.query || {};
+
+    return this.createUri(schema, query);
+  }
+
+  private createUri(schema: string, query: Record<string, unknown> = {}) {
+    return (
+      schema +
+      "://" +
+      this._hostname() +
+      this._port() +
+      this.opts.negotiatePath +
+      this._query(query)
+    );
+  }
+
+  private _hostname() {
+    const hostname = this.opts.hostname;
+    return hostname.indexOf(":") === -1 ? hostname : "[" + hostname + "]";
+  }
+
+  private _port() {
+    if (
+      this.opts.port &&
+      ((this.opts.secure && Number(this.opts.port !== 443)) ||
+        (!this.opts.secure && Number(this.opts.port) !== 80))
+    ) {
+      return ":" + this.opts.port;
+    } else {
+      return "";
+    }
+  }
+
+  private _query(query: Record<string, unknown>) {
+    const encodedQuery = encode(query);
+    return encodedQuery.length ? "?" + encodedQuery : "";
+  }
+}