Puppeteer 奇怪的作用域行为

Question

我正在尝试使用 puppeteer 自动填写表单，但它一直抛出 ReferenceError: text is not defined，即使它之前定义了 1 行并且 console.log 成功显示它。

这是引发错误的行： await page.$eval('#chat-message-text', el => el.value = text); 如果我用el.value = 'blablabla' 之类的东西填充它，效果会很好。

最奇怪的是console.log(text); 也能正常工作，然后它会抛出一个错误。

puppeteer.launch({ headless: false }).then(async browser => {

  const page = await browser.newPage()
  var cookie = [here are my cookies]

  await page.setCookie(...cookie)
  await page.goto('https://example.com')
  await page.waitFor(5000);

  await page.solveRecaptchas()
  console.log('Captcha was solved');
  await page.waitFor(5000);

  var text = JSON.parse(fs.readFileSync('/Users/apple/Desktop/test/text.json', 'utf8'));
  console.log("Sending text");
  console.log(text);
  await page.$eval('#chat-message-text', el => el.value = text);
  await page.waitFor(1000);
  await page.waitForSelector('button[class="btn btn-primary send-chat-btn"]');
  await page.click('button[class="btn btn-primary send-chat-btn"]');
  await page.waitFor(2000);
  await browser.close()
})

完整的错误日志：

(node:86035) UnhandledPromiseRejectionWarning: Error: Evaluation failed: ReferenceError: text is not defined
    at __puppeteer_evaluation_script__:1:19
    at ExecutionContext._evaluateInternal (/Users/apple/Desktop/test/node_modules/puppeteer/lib/ExecutionContext.js:122:13)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
  -- ASYNC --
    at ExecutionContext.<anonymous> (/Users/apple/Desktop/test/node_modules/puppeteer/lib/helper.js:111:15)
    at ElementHandle.evaluate (/Users/apple/Desktop/test/node_modules/puppeteer/lib/JSHandle.js:54:42)
    at ElementHandle.<anonymous> (/Users/apple/Desktop/test/node_modules/puppeteer/lib/helper.js:112:23)
    at ElementHandle.$eval (/Users/apple/Desktop/test/node_modules/puppeteer/lib/JSHandle.js:505:40)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
  -- ASYNC --
    at ElementHandle.<anonymous> (/Users/apple/Desktop/test/node_modules/puppeteer/lib/helper.js:111:15)
    at DOMWorld.$eval (/Users/apple/Desktop/test/node_modules/puppeteer/lib/DOMWorld.js:156:21)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
  -- ASYNC --
    at Frame.<anonymous> (/Users/apple/Desktop/test/node_modules/puppeteer/lib/helper.js:111:15)
    at Page.$eval (/Users/apple/Desktop/test/node_modules/puppeteer/lib/Page.js:345:29)
    at Page.<anonymous> (/Users/apple/Desktop/test/node_modules/puppeteer/lib/helper.js:112:23)
    at puppeteer.launch.then (/Users/apple/Desktop/test/app/test2.js:151:14)
    at <anonymous>
(node:86035) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:86035) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Answer 1

await page.$eval('#chat-message-text', (el, text) => el.value = text, TEXT);