Migrate to ESLint flat config for CI tests

[MikeMcC399]

What would you like?

Migrate tests running in .github/workflows/ci.yml to use ESLint flat configuration.

Why is this needed?

1. The script lint, used in CI, relies on running eslint.
2. The configuration for ESLint is contained in .eslintrc.cjs which is a standard configuration for ESLint v8.
3. ESLint configuration .eslintrc is deprecated in ESLint v9 and is planned to be removed in ESLint v10.
4. ESLint v8 support ceased on Oct 5, 2024.
5. ESLint flat configuration is the standard for ESLint v9 and later.
6. To ensure future support for internal linting of this repo, the deprecated .eslintrc.cjs configuration needs to be replaced by a flat configuration.

Other

Module	Original	Flat prerequisite	Current
eslint	8.33.0	8.57.1	8.57.1
eslint-plugin-square	24.0.0	unavailable	removed
eslint-plugin-node	11.1.0	unmaintained	eslint-plugin-n@17.11.1
eslint-plugin-unicorn	45.0.2	>= 50.0.0	56.0.0
eslint-plugin-jest	27.2.1	>= 27.9.0	27.9.0
@typescript-eslint/eslint-plugin	5.52.0	>= 7.0.0
@typescript-eslint/parser	5.52.0	>= 7.0.0
@typescript-eslint/utils	5.52.0	>= 7.0.0

Comments

1. eslint should be updated to the latest 8.* version to avoid any resolved issues supporting flat configurations in ESLint v8. Edit: done with PR chore(deps): update eslint to 8.57.1 #530
2. eslint-plugin-square says "It is generally not recommended for public usage outside of Square." and this plugin offers no support for flat configurations. Edit: done with PR chore(deps): replace eslint-plugin-square #539
3. eslint-plugin-node states "This project has been no longer maintained. Please consider to use https://github.com/eslint-community/eslint-plugin-n." Edit: done with PR chore(deps): migrate to eslint-plugin-n@17.11.1 #540

[MikeMcC399]

Partial resolution through:

• PR chore(deps): update eslint to 8.57.1 #530
• PR chore(deps): update eslint-plugin-jest to 27.9.0 #531

[ddzz]

I would recommend removing eslint-plugin-square entirely. Per its README, it's not meant for use in projects outside of Square's organization.

[MikeMcC399]

@ddzz

I would recommend removing eslint-plugin-square entirely. Per its README, it's not meant for use in projects outside of Square's organization.

Thank you for your guidance!

I guess it's no coincidence that eslint-plugin-square@24.0.0 currently used in this repo was released by @bmish, who was apparently working at Square at that time. I assume that this was done for convenience.

There are two issues mentioned in the original post supporting the removal:

• eslint-plugin-square says "It is generally not recommended for public usage outside of Square." and this plugin offers no support for flat configurations.

Removing eslint-plugin-square, whilst preserving the linting functioning it was providing, requires adding back some other ESLint plugins it uses.

[MikeMcC399]

@ddzz

I would recommend removing eslint-plugin-square entirely. Per its README, it's not meant for use in projects outside of Square's organization.

• See PR chore(deps): replace eslint-plugin-square #539 to implement your suggestion.

[MikeMcC399]

• A remaining prerequisite is Migrate @typescript-eslint/* linting to 7.* #545