Question

我是pupeteer的新手，不知道它的全部潜力。我有以下代码，从scrape返回结果。但是格式是一个长制表符分隔的字符串。我正在尝试获取正确的json。

(async () => {
const browser = await puppeteer.launch( {headless: true} );
    const page = await browser.newPage();
    await page.goto(url, {waitUntil: 'networkidle0'});

    let data = await page.evaluate(() => {
        const table = Array.from(document.querySelectorAll('table[id="gvM"] > tbody > tr ')); 
        return table.map(td => td.innerText);
    })

    console.log(data);
})();

这是html表：

<table cellspacing="0" cellpadding="4" rules="all" border="1" id="gvM" >
        <tr >
            <th scope="col">#</th><th scope="col">Resource</th><th scope="col">EM #</th><th scope="col">CVO</th><th scope="col">Start</th><th scope="col">End</th><th scope="col">Status</th><th scope="col">Assignment</th><th scope="col">&nbsp;</th>
        </tr>
        <tr >
            <td>31</td><td>Smith</td><td>618</td><td align="center"><span class="aspNetDisabled"><input id="gvM_ctl00_0" type="checkbox" name="gvM$ctl02$ctl00" disabled="disabled" /></span></td><td>&nbsp;</td><td>&nbsp;</td><td>AVAILABLE EXEC</td><td style="width:800px;">6F</td><td align="center"></td>
        </tr>
        <tr style="background-color:LightGreen;">
            <td>1</td><td>John</td><td>604</td><td align="center"><span class="aspNetDisabled"></span></td><td>1400</td><td>2200</td><td>AVAILABLE</td><td style="width:800px;">&nbsp;</td><td align="center"></td>
        </tr>
</table>

这就是我得到的：

[ '#\tResource\tEM #\tCVO\tStart\tEnd\tStatus\tAssignment\t ', '31\tSmith\t618\t\t \t \tAVAILABLE EXEC\t6F\t', '1\tJohn\t604\t\t1400\t2200\tAVAILABLE\t \t']

这就是我想要得到的：

[{'#','Resource','EM', '#','CVO','Start','tEnd','Status', 'Assignment'}, {'31','Smith', '618',' ',' ',' ',' ','AVAILABLE EXEC','6F'}, {'1','John', '604',' ',' ','1400 ','2200','AVAILABLE', ' '}]

我在下面应用了答案，但是无法重现结果。也许我做错了。您能解释一下我怎么搞的吗？

const context = document.querySelectorAll('table[id="gvM"] > tbody > tr ');

const query = (selector, context) => Array.from(context.querySelectorAll(selector));
console.log( 
    query('tr', context).map(row => 
        query('td, th', row).map(cell => 
        cell.textContent))  
);

此错误是什么意思？ (node:6204) 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:6204) [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

我认为这与Puppeteer无关，但与您在<table>上“迭代”的方式有关：

在尝试时，您只是在转储整行的文本内容，这会产生您要观察的结果。实际上，每个<tr>都需要获取其所有<td>（或<th>）元素：

const query = (selector, context) =>
  Array.from(context.querySelectorAll(selector));
  
console.log(

  query('tr', document).map(row =>
    query('td, th', row).map(cell =>
      cell.textContent))

)

<table>
  <tr>
    <th>col 1</th>
    <th>col 2</th>
    <th>col 3</th>
  </tr>
  <tr>
    <td>a</td>
    <td>b</td>
    <td>c</td>
  </tr>
  <tr>
    <td>x</td>
    <td>y</td>
    <td>z</td>
  </tr>
</table>

Answer 2

如果您需要表中的数组数组，则可以尝试这种方法，将所有行映射到行数组，并将所有单元格映射到行元素内的单元格数组（此变体使用Array.from()并将映射函数作为第二个参数）：

const data = await page.evaluate(
  () => Array.from(
    document.querySelectorAll('table[id="gvM"] > tbody > tr'),
    row => Array.from(row.querySelectorAll('th, td'), cell => cell.innerText)
  )
);

如何从pupeteer抓取的表中输出正确的json？

2 个答案: