Problem identified

Joomla 4 emits/creates ES5 javascript next to the current ES2018 ones. That was done because Internet Explorer was still alive but in few weeks it will be officially dead. Most of the tools also will adjust to this change, specifically autoprefixer and preset-env will move that browser to the dead ones. Thus the project has 2 options:

• adjust the scripts to keep creating the ES5 files (which are already broken, missing essential polyfills, etc, basically they are useless)
• or adjust the build tools to stop creating the ES5 files

Proposed solution

The proposal is to (obviously) drop the dead, unusable, ES5 files. The process needs some adjustments for the build tools and also adjusting the joomla.assets.json files.

Open questions

PS: If there's a decision to drop them I'll put the work to make it happen but time is critical here and this should be in the 4.2 early enough to have as much testing as possible

Context:

• #35739
• #35737
• #32148