`sass-loader` legacy JS API deprecation

Plan

• https://github.com/openedx/frontend-build/pull/639
• Upgrade sass-loader

Context (originally posted in #wg-frontend on slack)

Anyone have thoughts on the sass-loader legacy JS API deprecation? A warning pops up when running MFEs locally. There are some details about it here https://sass-lang.com/documentation/breaking-changes/legacy-js-api/#bundlers

A warning pops up when running MFEs locally. There are some details about it here https://sass-lang.com/documentation/breaking-changes/legacy-js-api/#bundlers

It seems to boil down to:

• We're using "sass-loader": "13.3.3" (https://github.com/openedx/frontend-build/blob/dac48980a9a2d4544d448c4096256a8cbca0a280/package.json#L89)(
• The "modern" API is not the default until sass-loader v16.0.0 (https://github.com/webpack-contrib/sass-loader/releases/tag/v16.0.0)

I see 2 options:

• Silence the deprecation for now (https://sass-lang.com/documentation/breaking-changes/legacy-js-api/#silencing-warnings)

OR

• Upgrade sass-loader (and maybe use sass-embedded? https://webpack.js.org/loaders/sass-loader/#api notes "Using modern-compiler and sass-embedded together significantly improve performance and decrease built time. We strongly recommend their use. We will enable them by default in a future major release."

I'm leaning towards silencing the deprecation warning until we cut Teak and upgrading for Ulmo, but I'm very open to hearing other thoughts on the matter!

Start with package.json, where sass-loader 13.3.3 is declared, and read the linked sass-loader and Sass legacy JS API documentation. Determine the intended upgrade path, then run the local MFE build to verify the deprecation warning is addressed and the build still works.