.window.switchTo() 建议编辑

                    .window.switchTo(windowHandle, [callback])
                

module.exports = {
 'switch to another window': function (browser) {
    browser
      .navigateTo('https://nightwatch.node.org.cn/__e2e/window/')
      .click('#openWindowBttn')
      .waitUntil(function () {
        // wait until window handle for the new window is available
        return new Promise((resolve) => {
          browser.window.getAllHandles(function (result) {
            resolve(result.value.length === 2);
          });
        });
      })
      .perform(async function () {
        const originalWindow = await browser.window.getHandle();
        const allWindows = await browser.window.getAllHandles();

        // loop through to find the new window handle
        for (const windowHandle of allWindows) {
          if (windowHandle !== originalWindow) {
            await browser.window.switchTo(windowHandle);
            break;
          }
        }

        const currentWindow = await browser.window.getHandle();
        browser.assert.notEqual(currentWindow, originalWindow);
      });
  },

  'switch to another window with ES6 async/await': async function (browser) {
    await browser.navigateTo('https://nightwatch.node.org.cn/__e2e/window/');
    await browser.click('#openWindowBttn');

    // wait until window handle for the new window is available
    await browser.waitUntil(async function () {
      const windowHandles = await browser.window.getAllHandles();

      return windowHandles.length === 2;
    });

    const originalWindow = await browser.window.getHandle();
    const allWindows = await browser.window.getAllHandles();

    // loop through available windows to find the new window handle
    for (const windowHandle of allWindows) {
      if (windowHandle !== originalWindow) {
        await browser.window.switchTo(windowHandle);
        break;
      }
    }

    const currentWindow = await browser.window.getHandle();
    await browser.assert.notEqual(currentWindow, originalWindow);
  }
}