Class Cdp

e2e/desktop-packaged/linux-vm/repro.mjs:74–112

// --- minimal CDP page client over the built-in WebSocket -------------------
class Cdp {
  #ws;
  #id = 1;
  #pending = new Map();
  constructor(ws) {
    this.#ws = ws;
    ws.addEventListener("message", (e) => {
      const m = JSON.parse(e.data);
      if (!m.id) return;
      const p = this.#pending.get(m.id);
      if (!p) return;
      this.#pending.delete(m.id);
      m.error ? p.reject(new Error(m.error.message)) : p.resolve(m.result);
    });
  }
  static connect(url) {
    return new Promise((resolve, reject) => {
      const ws = new WebSocket(url);
      ws.addEventListener("open", () => resolve(new Cdp(ws)), { once: true });
      ws.addEventListener("error", () => reject(new Error(`CDP connect failed ${url}`)), {
        once: true,
      });
    });
  }
  cmd(method, params = {}) {
    const id = this.#id++;
    const p = new Promise((resolve, reject) => this.#pending.set(id, { resolve, reject }));
    this.#ws.send(JSON.stringify({ id, method, params }));
    return p;
  }
  async eval(expression) {
    const r = await this.cmd("Runtime.evaluate", {
      expression,
      awaitPromise: true,
      returnByValue: true,
    });
    return r?.result?.value;
  }
}

const pageWsFor = async (debugPort) => {
  const targets = await fetch(`http://127.0.0.1:${debugPort}/json/list`).then((r) => r.json());