Wait for DOM content before snapping

It would be great if it was possible to only start taking the screenshots once some specific content was on the DOM. Puppeteer has a waitForSelector function (docs), however I’ve not had success implementing this, I imagine this is because the content I am waiting for is rendered by JS.

[Asheboy]

@tungs I’ve put an implementation of what I needed here. I went down the route of only capturing while a selector was on the DOM. It means that the webpage can have more control over the start and end times of the capture.

Happy to make changes and submit a PR, shoot over any criticism.

[tungs]

@RhinoW, I’m on the fence about this, though I’m leaning towards the overall idea; the implementation seems straightforward and generally useful, though it feels a little feature bloaty.

If I do implement it, it would probably be as two functions: a start function (like shouldStartCapture) that would take page as an argument and resolve to true to begin capturing and an end function (like shouldEndCapture) that would take page as an argument and resolve to true to prematurely end capturing. The function names might need a little tweaking to make it clear that virtual time is being incremented.

This should give you the flexibility to check for a range of things (e.g. see if an element exists or a global variable is set to a certain value).

Would this work for your use case? I realize that this would require specifying a function instead of a string, so it can be less friendly than Asheboy’s implementation.