How to get text from an element:
const element = await page.$('.some-class');
const text = await page.evaluate(element => element.textContent, element);
// or
const text = await page.evaluate(element => element.innerText, element);
const text = await page.$eval('#some-id', el => el.textContent);
How to wait for an element to disappear or removed from DOM:
await page.waitForSelector('.some-class', {hidden: true});