dialog.js

let resolveDialogClosePromise;
const dialogClosePromise = new Promise(resolve => {
  resolveDialogClosePromise = resolve;
});
this.page.on('dialog', async dialog => {
  await dialog.accept();
  resolveDialogClosePromise();
});

await Promise.all([this.page.waitForNavigation(), this.page.click('#send')]);
this.gid = this.page.url().split('gid=')[1];
console.log('gid', this.gid);

await Promise.race([dialogClosePromise, util.sleep(20000)]);