ESM Configuration Tracking

[thescientist13]

Overview

Coming out of the migration to ESM in #532, one of the "lagging" aspects of the migration is how tools handle their configuration files. Most of them actually do not support an ESM configuration file, so for these cases, you would have to use an extension of .cjs and still use CommonJS.

The below is a list of them, broken down between dependencies and devDependencies

dependencies

The impact configuration files related to our plugins, like Babel, PostCSS, etc

1. PostCSS - (requires two postcss config files for now) - ESM only configuration for PostCSS plugin #1312
   • ES module support postcss/postcss-cli#387
   • CosmicConfig (underlying dep) - support mjs extensions out of box cosmiconfig/cosmiconfig#224
2. Babel
   • Support for ESM style Babel config files, calling Babel in async fixed? babel/babel-loader#894

devDependencies

These impact configuration files for Greenwood's own development, like ESLint, StyleLint, etc

1. Stylelint
   • Move to ESM stylelint/stylelint#5291
2. ESLint
   • Implement Flat Config eslint/eslint#13481
   • Also, ESLint does not support TLA yet or import.meta
   • Does not support Import Attributes either, which means a custom parser is needed for now - Support of `assert {type: "json"}` eslint/eslint#15305
     • which conflicts with certain plugins like markdown plugin - Doesn't work with custom parser eslint/markdown#221
3. Mocha - 🚀 Feature: ESM configuration file mochajs/mocha#5049
4. Tailwind - https://tailwindcss.com/blog/tailwindcss-v3-3#esm-and-typescript-support

Misc

Random stuff related to the ESM migration worth keeping loose track of

• import json support in NodesJS in cli/src/index.js, like for reading package.json
• Had to fallback to require for require.resolve.paths, does there exist a similar convention for ESM, e.g. import.meta.resolve.paths
• migrate more of our usages of path => new URL, more of a chore, and could be done post

[thescientist13]

Good news, CosmicConfig now supports ESM! - cosmiconfig/cosmiconfig#224 (comment)

[thescientist13]

I think as far as first party config files go, we'll be covered after #1312 which should be released in an alpha soon so closing this one out.

[thescientist13]

Looks like Import Attributes are now supported as of ESLint v9.14.0 🎉
https://github.com/eslint/eslint/blob/main/CHANGELOG.md