Add progressively enhanced file upload component

[querkmachine]

As part of post-audit investigations, a spike into layering a new UI onto the File upload component that should be a bit more friendly to assistive technologies. alphagov/govuk-design-system#4031

Note: This hasn't actually been tested across browsers and ATs yet,

Changes

• Progressively enhances the file input of the File upload component with a custom button and file selection display.
  • This new UI localisable. This adds the potential for buttons to better describe what needs uploading.
  • As much as possible, this new UI behaves similarly to the browser's native controls (e.g. can click on the label or input text to activate the component; supports multiple, accepts and capture attributes; etc.)
• Adds a visual drop zone if a file is dragged over the input.

Thoughts

• There are some features that are not supported yet. For example, the button will still appear useable even if the underlying input has been disabled.
• The native file input is visually hidden but is still exposed to screen readers. I wasn't sure if I could (or should) hide it from them, as it may contain context that the 'enhanced' controls do not. Further testing needed.
• This has been developed to pretty closely resemble native file inputs as they appear in Chromium browsers. We may be interested in styling them more similarly to other form inputs (e.g. having a black border around it.)
• The visual drop zone currently only appears when dragging over the input itself. It may be preferable for it to appear if a file is dragged over anywhere on the page.

[github-actions]

📋 Stats

File sizes

File	Size
dist/govuk-frontend-development.min.css	120.14 KiB
dist/govuk-frontend-development.min.js	47.01 KiB
packages/govuk-frontend/dist/govuk/all.bundle.js	100.92 KiB
packages/govuk-frontend/dist/govuk/all.bundle.mjs	94.8 KiB
packages/govuk-frontend/dist/govuk/all.mjs	1.32 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend-component.mjs	1.74 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend.min.css	120.13 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend.min.js	47 KiB
packages/govuk-frontend/dist/govuk/i18n.mjs	5.55 KiB
packages/govuk-frontend/dist/govuk/init.mjs	7.5 KiB

Modules

File	Size (bundled)	Size (minified)
all.mjs	88.93 KiB	44.54 KiB
accordion.mjs	26.58 KiB	13.41 KiB
button.mjs	9.09 KiB	3.78 KiB
character-count.mjs	25.39 KiB	10.9 KiB
checkboxes.mjs	7.81 KiB	3.42 KiB
error-summary.mjs	10.99 KiB	4.54 KiB
exit-this-page.mjs	20.2 KiB	10.34 KiB
file-upload.mjs	19.5 KiB	10.13 KiB
header.mjs	6.46 KiB	3.22 KiB
notification-banner.mjs	9.35 KiB	3.7 KiB
password-input.mjs	18.24 KiB	8.33 KiB
radios.mjs	6.81 KiB	2.98 KiB
service-navigation.mjs	6.44 KiB	3.26 KiB
skip-link.mjs	6.4 KiB	2.76 KiB
tabs.mjs	12.04 KiB	6.67 KiB

View stats and visualisations on the review app

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Action run for 2e256f5

[selfthinker]

I've started testing this today. But I've only tested with Dragon so far.

Unfortunately it doesn't work. Roughly 9 out of 10 times saying "click choose file" or "click button" only focused on the button but didn't open the file dialog. And weirdly 1 out of 10 times it did. But I didn't do anything differently between when it did and when it didn't.

When we've figured out why this is happening I will test again, including in other assistive technologies.

[owenatgov]

Rebased this whilst I do some local testing

[edwardhorsford]

Just in case it's helpful - we had a styled upload button on the passport service - which has presumably been tested by DAC multiple times.

[querkmachine]

@edwardhorsford Do you know if it was tested in Dragon NaturallySpeaking and, if so, whether it exhibited the same issues described by @selfthinker?

[edwardhorsford]

@edwardhorsford Do you know if it was tested in Dragon NaturallySpeaking and, if so, whether it exhibited the same issues described by @selfthinker?

I assume it was tested with it as DAC did the testing. But I don't recall more than that. You could try on the live service to see how it works now...

[querkmachine]

Adding aria-hidden to the input is apparently ignored by Chromium and raises an error in the console.

Blocked aria-hidden on a <input> element because the element that just received focus must not be hidden from assistive technology users. Avoid using aria-hidden on a focused element or its ancestor. Consider using the inert attribute instead, which will also prevent focus. For more details, see the aria-hidden section of the WAI-ARIA specification at https://w3c.github.io/aria/#aria-hidden.

tabindex="-1" alone probably suffices for stopping tabbing but I'm not sure if it can prevent keyboard navigation entirely, especially of the kind that screenreaders do which is on a level not easily detected by webpages.

[selfthinker]

DAC's solution was using the disabled attribute.
But they were partly using it to show the uploaded file.