refactor(gatsby-plugin-manifest): misc code and doc updates

[moonmeister]

Description

Code and Docs updates for gatsby-plugin-manifest

• Finished moving to module imports
• Finished migrating off of bluebird and onto async/await (order of magnitude speed increase)
• Major doc updates
• Improve logging output for generation

[moonmeister]

One thing I did want to open up for discussion on this is using gatsby-plugin-sharp as a peer dependency instead of directly depending on sharp. I'm not sure if there would be any benefits or drawbacks either way. It crossed my mind and wanted to see what others thought.

[DSchau]

This looks great! I'll take a deeper dive on this in a bit--but could you clarify this?

Finished migrating off of bluebird and onto async/await (order of magnitude speed increase)

Do you have any metrics/benchmarks/etc. for this?

[moonmeister]

@DSchau haha I just mentioned this chat but I'll put it here for everyone:

when I eliminated the final line of code requiring bluebird and replaced it with a native promise I saw icon generation drop from between 200ms and 900ms to down to ~13ms.

I'm running latest node 10 lts on linux.

[moonmeister]

Rebased after 2 different manifest related PRs and fixed 2 bugs from #12794

[moonmeister]

Added tests and refactored the icon options merge as described here: #12794 (comment). Also, fixed bug that was not letting config merge happen (thank you testing).

[moonmeister]

Moved bug fixes to #12907

[moonmeister]

@DSchau Well, bench marking proved I was wrong. 😞 Evidently it was just a strange fluke that I saw execution time drop. That or my bench mark is inaccurate. 🤷‍♂️ I've added a bench mark for testing the execution time of onPostBootstrap in the manifest plugin.

[wardpeet]

I resolved the conflicts but I wasn't sure of

<<<<<<< manifest-cleanup -- Incoming Change
The `icon_options` object may be used to iteratively configure the [default icon array](#automatic-mode-configuration). Any options included in this object will be merged with each item of the `icons` array. This may be used in Automatic and Hybrid modes.
=======
The `icon_options` object may be used to iteratively add configuration items to the `icons` array. Any options included in this object will be merged with each object of the `icons` array (custom or default). Key value pairs already in the `icons` array will take precedence over duplicate items in the `icon_options` array.
>>>>>>> master -- Current Change

I used master when merging but feel free to change back what you had on this PR

[moonmeister]

You made the right call.

[moonmeister]

@DSchau @wardpeet Anything I can do to get this done or is it ready to be merged? The only other thing that's been on my mind is whether we should remove the dependency on sharp and use gatsby-plugin-sharp. I'm completely unaware of why we' prefer one method or the other.

[wardpeet]

Thanks for pinging!

This PR is pretty hard to review as so many things have changed, you added functionality & changed a lot of tests. It looks like you didn't change behaviour in the tests except omitting data but now it's really hard to actually validate if your changes are not breaking.

I'll probably ask some dumb questions in the review to make sure I've understood everything.

[moonmeister]

@wardpeet Sorry! I'll keep PRs smaller in the future. yes, there are no new features. I just organized docs and tests. In the test work I found a couple bugs I squashed. Also each commit is generally one change. Maybe reviewing each commit individually might be helpful. I'll be around to answer questions

[wardpeet]

I've tested the code with the old tests and it seems to work fine.

I moved to createContentDigest from gatsby instead of our own.

[moonmeister]

@wardpeet Awesome. I don't think the built-in content digest existed when I wrote that code originally. I think it was still in discussion glad you moved over to that! Thanks!

[sidharthachatterjee]

Thanks for all your work in this @moonmeister!

Published in gatsby-plugin-manifest@2.0.27