Support waitForElementToBeRemoved

[umpox]

waitFor and find* queries are supported but waitForElementToBeRemoved is not currently. It would be useful to add this async util to avoid having to write boilerplate code around waitFor and expect

waitForElementToBeRemoved - DOM Testing Library

[avimar]

waitForElementToBeRemoved seems to pass in a selector.
I'm needing to wait for an actual element to be removed. (I have a "continue" button on each stage of a form, and because of a
transition, there's a moment that you can see both "continue" buttons.)

Apparently, you can check if the elementHandle is still connected with await elementHandle.evaluate(el => el.isConnected) puppeteer/puppeteer#640 (comment)

[avimar]

Here's my generic function that you can include under the MIT license to wait for an actual elementHandle to be removed. I didn't write the sleep function... it should be generic enough, though...

This code seems to work as a generic function:

function sleep(ms) {
	return new Promise((resolve) => {
		setTimeout(resolve, ms);
		});
	}
async function waitForElementHandleToBeRemoved(elementHandle,waitMax=5000,waitStep=100){
	const timeStart = new Date().valueOf();
	var elementVisible = true;
	var timeNow=timeStart;
	while((timeNow-timeStart)<waitMax && elementVisible){
		await sleep(waitStep);
		elementVisible = await elementHandle.evaluate(el => el.isConnected);
		timeNow = new Date().valueOf();
		}
	if(!elementVisible) return true;
	throw new Error('element still visible after '+waitMax+'ms');
	}