Minor bug: bad screenshot path says "Unsupported screenshot mime type: null"

Puppeteer gives a bizarre error message when the path to which you try to write a screenshot is bad: Unsupported screenshot mime type: null

The file path is not a mime type issue.

This was previously reported as #3629, but the original reporter closed the report following self diagnosis.

I believe that this is because the file’s extension is being used to auto-detect the desired mime type, and I had not set the extension initially.

[Yokutto]

Your file path needs to terminate with a image mime-type Example: /path/to/screenshot .png

screenshot.png will be the name of screenshot 😉

[StoneCypher]

yes, thanks, that’s what i said in my issue

I believe that this is because the file’s extension is being used to auto-detect the desired mime type, and I had not set the extension initially.

that’s actually not correct behavior. mime types are not inferred from file extensions.

also, this error message is badly wrong