Firefox 'Add to Home Screen'

[redrockvp]

Description

So Firefox now supports PWAs with an "Add To Home Screen" button in Firefox for Android 58.
However it doesnt seem like gatsby-plugin-offline supports this out of the box.

It would be great if it did 😄

More details here: https://developer.mozilla.org/en-US/Apps/Progressive/Add_to_home_screen

[KyleAMathews]

That'd be great! Would you like to work on a PR adding support?

[redrockvp]

No guarantees, but I'll give it a bash :)

[redrockvp]

So it seems, upon further investigation, like a .json file works as well. This seems to be more an issue of an unclear spec. However, .webmanifest is the current latest spec: https://w3c.github.io/manifest/.
You can confirm this by visiting gatsbyjs.org on Firefox 58 for Android.

So it might be worth updating gatsby-plugin-manifest to use it?
@KyleAMathews your thoughts on this?

I also noticed that gatsby-plugin-manifest deosnt seem to take --prefix-paths into account and always just uses \ as the start_url parameter, which does seem to cause issues from my very initial testing. I think that the parameter should be set to \index.html and also that it should include the prefix path if there is one, to match the current PWA standards.

[m-allanson]

The .webmanifest update was done in #5128, thanks @AurelioDeRosa!

[m-allanson]

@HTEredrock thanks for raising this, I'm going to close it as your initial request has been handled. If you're seeing an issue with --prefix-paths in gatsby-plugin-manifest could you open a new issue and fill out the issue template?