Add contribution docs on adding component configuration options

[querkmachine]

I noticed yesterday that, although we've seemingly settled on a method of adding configuration options (including localisation strings) to components, we had only documented how to use the ones we added from an end user's perspective.

Here's some scratchy documentation on how to add new configuration options and guidelines for naming them.

[colinrotherham]

We should still re-visit this, it's useful

But will need to catch up with:

• Migrate JavaScript to ES2015 classes #3771
• Add Babel to transform ES2020 public and static class fields #3820
• Remove component init() methods and initialise in constructor #4011

[querkmachine]

The documentation here has since fallen out of date with subsequent changes to JavaScript architecture.

As I wasn't involved in those updates and don't particularly have knowledge of what they are, I'm encouraging someone more familiar to update this in my stead. If it doesn't get picked up in a reasonable amount of time, I'll likely close this off instead.

[github-actions]

📋 Stats

File sizes

File	Size
dist/govuk-frontend-development.min.css	113.24 KiB
dist/govuk-frontend-development.min.js	42.21 KiB
packages/govuk-frontend/dist/govuk/all.bundle.js	87.21 KiB
packages/govuk-frontend/dist/govuk/all.bundle.mjs	81.95 KiB
packages/govuk-frontend/dist/govuk/all.mjs	4.17 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend-component.mjs	359 B
packages/govuk-frontend/dist/govuk/govuk-frontend.min.css	113.23 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend.min.js	42.2 KiB
packages/govuk-frontend/dist/govuk/i18n.mjs	5.55 KiB

Modules

File	Size (bundled)	Size (minified)
all.mjs	77.67 KiB	40.19 KiB
accordion.mjs	22.71 KiB	12.85 KiB
button.mjs	5.98 KiB	2.69 KiB
character-count.mjs	22.4 KiB	9.92 KiB
checkboxes.mjs	5.83 KiB	2.83 KiB
error-summary.mjs	7.89 KiB	3.46 KiB
exit-this-page.mjs	17.1 KiB	9.26 KiB
header.mjs	4.46 KiB	2.6 KiB
notification-banner.mjs	6.26 KiB	2.62 KiB
password-input.mjs	15.15 KiB	7.25 KiB
radios.mjs	4.83 KiB	2.38 KiB
skip-link.mjs	4.39 KiB	2.18 KiB
tabs.mjs	10.13 KiB	6.11 KiB

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Action run for 78b0795

[colinrotherham]

@querkmachine I've given it a rapid work-in-progress refresh, something along these lines?

[romaricpascal]

That's a neat piece of doc! 🙌🏻 I'd be keen to merge it as it is and add some extra information around typing the configuration in a separate PR (as we probably need to think if the info fits here or in a more generic using-types piece of docs).

@colinrotherham @querkmachine Do you think there's anything holding it from being merged? If not, let's press that green button 😊

[colinrotherham]

@romaricpascal Just a double check over my quick edits?

Aware that lots of the examples given will fail due to missing JSDoc though, should we include it?

Will also need a big update once we fix how components set up their options after #4230

[querkmachine]

@romaricpascal It's been a while so I'm definitely not sure of how accurate parts of it are at this point, but better to have something that we can iterate upon rather than sitting on it for much longer.

[querkmachine]

Going to merge this on the basis that having something to iterate upon is probably better than letting this languish and grow outdated again.