2017-09-07 40 views
13

我試圖在Puppeteer中將變量傳遞給page.evaluate()函數,但是當我使用以下非常簡化的示例時,變量evalVar未定義。Puppeteer:在.evaluate()中傳遞變量

我是Puppeteer的新手,找不到任何可以構建的示例,所以我需要幫助將該變量傳遞給page.evaluate()函數,以便我可以在裏面使用它。

const puppeteer = require('puppeteer'); 

(async() => { 

    const browser = await puppeteer.launch({headless: false}); 
    const page = await browser.newPage(); 

    const evalVar = 'WHUT??'; 

    try { 

    await page.goto('https://www.google.com.au'); 
    await page.waitForSelector('#fbar'); 
    const links = await page.evaluate((evalVar) => { 

     console.log('evalVar:', evalVar); // appears undefined 

     const urls = []; 
     hrefs = document.querySelectorAll('#fbar #fsl a'); 
     hrefs.forEach(function(el) { 
     urls.push(el.href); 
     }); 
     return urls; 
    }) 
    console.log('links:', links); 

    } catch (err) { 

    console.log('ERR:', err.message); 

    } finally { 

    // browser.close(); 

    } 

})(); 

回答

22

你必須變量作爲參數傳遞給pageFunction這樣的:

const links = await page.evaluate((evalVar) => { 

    console.log(evalVar); // should be defined now 
    … 

}, evalVar); 

的參數也可以被序列:https://github.com/GoogleChrome/puppeteer/blob/master/docs/api.md#pageevaluatepagefunction-args

+0

謝謝,這是做到了:)非常感謝! –

+0

你好,你會如何傳遞多個變量? – chitzui

+1

此外,我真的不能傳遞一個函數: var myFunction = function(){console.log(「hello」)}; 等待page.evaluate(func => func(),myFunction); 給了我:'評估失敗:TypeError:func不是函數'..爲什麼? – chitzui

2

我鼓勵你堅持這種風格,因爲它更方便可讀

let name = 'jack'; 
let age = 33; 
let location = 'Berlin/Germany'; 

await page.evaluate(({name, age, location}) => { 

    console.log(name); 
    console.log(age); 
    console.log(location); 

},{name, age, location});