How to Implement a Time Delay in Puppeteer?

Waiting for a Specified Duration in Puppeteer

In Puppeteer, developers occasionally encounter the need to pause execution for a defined period before proceeding to the next line of code. While attempts to incorporate setTimeout within evaluate functions might seem like a viable solution, they often encounter unexpected behavior.

Solutions for Pausing Execution

1. Promise-Based Delay: A simple and effective method is to define a delay function as a promise and then invoke it whenever a pause is desired.

function delay(time) {
   return new Promise(function(resolve) { 
       setTimeout(resolve, time)
   });
}

For instance, to pause for 4 seconds:

console.log('before waiting');
await delay(4000);
console.log('after waiting');

2. page.waitForTimeout: Puppeteer provides a built-in function specifically designed for waiting.

await page.waitForTimeout(4000)

3. Resolved Evaluate: If the page.evaluate function is preferred, it's crucial to resolve the promise after the desired delay has elapsed.

await page.evaluate(async() => {
    await new Promise(function(resolve) { 
           setTimeout(resolve, 1000)
    });
});

Recommendation

While the evaluate approach can be utilized, the first two methods are generally more straightforward and efficient.

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