Read component data from built fixtures.json

[colinrotherham]

We currently build two JSON files for the GOV.UK Design System

These are generated from component YAML files but aren't currently tested:

• fixtures.json from ${componentName}.yaml
• macro-options.json from ${componentName}.yaml

This PR updates all "component data" helpers to read from fixtures.json instead of YAML

The Review app no longer needs to access govuk-frontend/src YAML files

• Test that documented component options match the templates #1139

[romaricpascal]

Looks neat, just need to confirm why we've moved to reading the list of components from dist rather than src (as it's a bit of a hidden requirement for that function that you need to have built the package before it can be run and may cause some confusion).

[romaricpascal]

Just to confirm: are we're adding the requirement of reading from dist rather than src to ensure we read the list that's inside the package itself (and avoid potential missing components from older versions)?

[colinrotherham]

Yeah that's the one, added an example in #4042 (comment)

[romaricpascal]

Makes sense given we talk of macro "options" all around 🙌🏻

[colinrotherham]

Thanks @romaricpascal

Looks neat, just need to confirm why we've moved to reading the list of components from dist rather than src (as it's a bit of a hidden requirement for that function that you need to have built the package before it can be run and may cause some confusion).

Yeah it was one of your future suggestions from #3498 (comment)

So for now, I think we can live with loading the YAML files from src. Might be worth using fixtures.json in the future though as it contains the pre-rendered examples (would need to check that they're all there though), but we can leave it out for now.

It came up again whilst looking at stats for legacy releases, for example:

1. Checkout main with Exit this page and Task list components
2. Install a legacy version for stats, e.g. GOV.UK Frontend v4.6.0

But you'll notice that our helpers:

• List Exit this page and Task list for components
• List Exit this page for componentsWithJavaScript

We were looping directories in packages/govuk-frontend/src not the locally installed version

[romaricpascal]

Good to go! ⛵