--start-server-command

[paulirish]

carrying over from https://github.com/GoogleChrome/web.dev/pull/1757/files#r339844263 .....

zeit used to allow you to run your own webserver (they're now just static site and serverless functions).. but at the time they'd look for a now-start npm script first.. and if not they'd use a start npm script.

that's one option here too.. we look for start:lhci followed by start. if there's neither we log an error.

One downside here in doing all this automagically is that we don't really know exactly how long to wait after starting the server before we can begin collecting. i guess some sites have complicated servers that don't kick off instantly?

[patrickhulce]

There was discussion about this in a thread with surma, but tl;dr I very strongly argued against doing any of regular command detection automatically (i.e. automatically using npm start). Most of the servers provided by framework CLIs do not serve production assets and/or do not provide realistic production environment settings like asset compression (preact is the only one I know of that does this). Almost no one will know to look for this and they'll be much worse off than following the npm run build && lhci autorun method.

Automatically supporting a start:lhci seems like a good compromise to me 👍

[patrickhulce]

fixed by #46