Javascript puppeteer：在继续下一行之前等待 N 秒
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puppeteer: wait N seconds before continuing next line
提问by Vivien Pipo
in puppeteerI would like to wait a defined time before going to the next line of code.
在puppeteer 中，我想在转到下一行代码之前等待定义的时间。
I've tried to put a setTimeoutin an evaluate function but it seems to be simply ignored
我试图将 asetTimeout放入一个评估函数中，但它似乎被简单地忽略了
console.log('before waiting');
await page.evaluate(async() => {
setTimeout(function(){
console.log('waiting');
}, 4000)
});
console.log('after waiting');
This code don't wait and just write before waitingand after waiting
这段代码不等待，只是在等待之前和等待之后写
Do you know how to do this?
你知道怎么做吗？
回答by Md. Abu Taher
You can use a little promise function,
你可以使用一点promise函数，
function delay(time) {
return new Promise(function(resolve) {
setTimeout(resolve, time)
});
}
Then, call it whenever you want a delay.
然后，只要你想延迟就调用它。
console.log('before waiting');
await delay(4000);
console.log('after waiting');
If you must use puppeteer use the builtin waitFor function.
如果您必须使用 puppeteer，请使用内置的 waitFor 函数。
await page.waitFor(4000)
If you still want to use page.evaluate, resolve it after 4 seconds. You are not resolving anything.
如果还想用page.evaluate，4秒后解决。你没有解决任何问题。
await page.evaluate(async() => {
await new Promise(function(resolve) {
setTimeout(resolve, 1000)
});
});
But I guess you can simply use the first two examples.
但我想你可以简单地使用前两个例子。
回答by Grant Miller
You can use one of the following options to wait for one second:
您可以使用以下选项之一等待一秒钟：
await page.waitFor(1000);
await frame.waitFor(1000);
await new Promise(r => setTimeout(r, 1000));
Alternatively, there are many Puppeteer functions that include a built-in delayoption, which may come in handy for waiting between certain events:
或者，有许多包含内置delay选项的Puppeteer 函数，这可能会在某些事件之间进行等待时派上用场：
// Click Delay
// Time to wait between mousedown and mouseup in milliseconds. Defaults to 0.
await page.click('#example', {delay: 1000});
await frame.click('#example', {delay: 1000});
await elementHandle.click({delay: 1000});
await page.mouse.click(0, 0, {delay: 1000});
// Type Delay
// Time to wait between key presses in milliseconds. Defaults to 0.
await page.type('#example', 'Hello, world!', {delay: 1000});
await frame.type('#example', 'Hello, world!', {delay: 1000});
await elementHandle.type('Hello, world!', {delay: 1000});
await page.keyboard.type('Hello, world!', {delay: 1000});
// Press Delay
// Time to wait between keydown and keyup in milliseconds. Defaults to 0.
await elementHandle.press('Backspace', {delay: 1000});
await page.keyboard.press('Backspace', {delay: 1000});
回答by Huckleberry Carignan
I've been using:
我一直在使用：
await page.waitFor(3000);
Where 3000 is Milliseconds And that seems to be working for me.
其中 3000 是毫秒 这似乎对我有用。
回答by Yordan
Try this function.
试试这个功能。
function sleep(ms) {
return new Promise(resolve => setTimeout(resolve, ms));
}
to use it
使用它
async function demo() {
console.log('Waiting...');
await sleep(3000);
console.log('ok');
}
demo();
回答by Xin
await new Promise(_func=> setTimeout(_func, 5000));
回答by atopcu
Your syntax is incomplete.
Try this...
你的语法不完整。
尝试这个...
await page.evaluate(async() => {
setTimeout(function(){
console.log('waiting');
}, 4000)
});
