Console.log() from page.evaluate() not working

[Nicolas-vrcc]

Hello,

I'm trying to console.log() in a page.evaluate() function and it's not working...
Any solutions ?

Thank you !

[Everettss]

It is working but it's not outputting to node environment console. Have a look at page.on('console', callback). Here is an example from docs:

page.on('console', msg => {
  for (let i = 0; i < msg.args.length; ++i)
    console.log(`${i}: ${msg.args[i]}`);
});
page.evaluate(() => console.log('hello', 5, {foo: 'bar'}));

[c094728]

everything that is run inside the page.evaluate function is done in the context of the browser page. The script is running in the browser not in node.js so if you log it will show in the browsers console which if you are running headless you will not see. You also can't set a node breakpoint inside the function.

[ChristosChristofidis]

you can capture it with page.on('console' even in headless

[proton1k]

@Everettss thanks for the example, but It does not seem to work with evaluateHandle though. And neither for evaluate method in my case. Could you please explain the current case how page.on carries .log call ? Or better to read the source code for page.on ?

[hungcao181]

Page.on('console', (msg) => {}) actually fired, but the example will not work because msg.args is undefined. Inside the callback, just console.log(msg) we will see what is inside.
Actually msg is of type ConsoleMessage, which provide 3 methods args(), text(), type()
We should call these 3 methods inside the callback instead of just access them as properties.
https://pptr.dev/#?product=Puppeteer&version=v1.7.0&show=api-class-consolemessage

[hungcao181]

Just one more thing, the page.on('console', callback) should be registered before any console.log statement can be called

[GuoZhaoHui628]

谢谢 @c094728 解答，如果还有问题，戳右边链接。https://guozh.net/puppeteer-page-evaluate-consolelog-not-working/

[ghost]

For anyone looking at this issue now, in the latest version, you'll need to do this instead:

for (let i = 0; i < msg._args.length; ++i)
    console.log(`${i}: ${msg._args[i]}`);

args has been replaced with _args

[asamountain]

page.on('console', msg => {
for (let i = 0; i < msg._args.length; ++i)
    console.log(`${i}: ${msg._args[i]}`);
});

as referred, @Ed-Ed @Everettss above code does work!
Thank you guys

[ezy]

For the full message logs this worked for me:

page.on("console", msg => console.log("PAGE LOG:", msg));

[iniatse]

this does not trigger for console.log() within the site which is loaded. It only triggers when using page.evaluate()

[nickofthyme]

Slight improvement to @ezy's solution. This will print the message type and the resolved message text from the console args.

page.on('console', (msg) => console[msg._type]('PAGE LOG:', msg._text));

[whoisjuan]

I don't know why this hasn't been mentioned here but simply setting dumpio: true when setting puppeteer.launch options will pass up all the console logs inside all your page.evaluate.

[Hamisakim]

@whoisjuan Thanks!!
if anyone runs into this issue, this is the snippet needed

  const browser = await puppeteer.launch({
    dumpio: true
  })

[lgh06]

in 2023 Sep, I have to use page.on('console', (msg) => console[msg.type()]('PAGE LOG:', msg.text()));

[cantonalex]

I'm also having this problem seems to have stopped working after 21.1.1