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Migrate to Sass module system (@use)

See original GitHub issue

What

Update GOV.UK Frontend to use the new @use syntax internally to import dependencies, and to be consumed using @use.

Why

The Sass module system has been introduced, aiming to address some of the issues with the @import rule.

The @import rule, and most global functions will eventually be deprecated, and then removed from Sass.

Moving to @use will allow us to revisit and simplify the way that GOV.UK Frontend is implemented, without the limitations of @import – for example namespacing, and the govuk-exports mixin.

Depends on

Stable support for @uses in LibSass – which probably means a stable version with support having been out for 3-6 months.

(The ‘future plans’ section of the module system blog post sets a hard limit of October 2021 for deprecating @import, which we could also do, but we’d need to have a better understanding of the impact it’ll have on our users.)

Further detail

We would only support compilation using Dart Sass.

We would drop support for the other compilers, which are deprecated and will not be updated to use the new module system:

Ruby Sass, deprecated as of 26 March 2019
LibSass, deprecated as of 5 Aug 2020

Issue Analytics

State:
Created 3 years ago
Reactions:1
Comments:6 (5 by maintainers)

Top GitHub Comments

1reaction

querkmachinecommented, Apr 7, 2022

Apparently Dart Sass adoption is currently around 66%.

1reaction

querkmachinecommented, Mar 29, 2022

I’ve been digging around the Sass repos for new information on when @import is going to be deprecated or removed, given there hasn’t been any official update that the date was changed from October 2021.

The comment here (December 2021) seems to imply that the deprecation did not take place due to the ecosystem not migrating to Dart Sass as quickly as anticipated, with no new date being set for it to take place. https://github.com/sass/sass/issues/3223#issuecomment-1002813284

This follow up I’ve asked indicates that they consider 70–80% adoption of Dart Sass to be the threshold for them to start the deprecation process. https://github.com/sass/sass/issues/3276#issuecomment-1076789429 — The current metrics don’t appear to be publicly available at this time, however.