🚀 Feature: Implement unnecessaryUndefinedDefaults rule (TypeScript)

[JoshuaKGoldberg]

Feature Request Checklist

• I have pulled the latest main branch of the repository.
• I have searched for related issues and found none that matched my issue.

Overview

Per flint.fyi/rules, Flint is intended to have a unnecessaryUndefinedDefaults rule in the TypeScript plugin (ts). It'll behave roughly equivalently to the existing implementations in other linters to start. This issue tracks adding that rule.

Adding this rule will entail creating the following new source files:

• packages/ts/src/rules/unnecessaryUndefinedDefaults.ts: implementation of the rule itself
• packages/ts/src/rules/unnecessaryUndefinedDefaults.test.ts: tests for the rule
• packages/site/src/content/docs/rules/ts/unnecessaryUndefinedDefaults.mdx: documentation of the rule

Additionally, the following files will need to be edited:

• packages/comparisons/src/data.json: Comparisons data will need to mention the rule is now "status": "implemented"
• packages/ts/src/plugin.ts: Included rules should have the new one inserted in alphabetical order

Additional Info

Existing rules in other linters:

• Biome: noUselessUndefined
• ESLint: unicorn/no-useless-undefined
• Oxlint: unicorn/no-useless-undefined

❤️‍🔥

[lishaduck]

This probably need to be type-aware, see the comment:

Where passing undefined as argument is required is due to bad TypeScript types in functions, in which case you can use checkArguments: false option.

Ideally we wouldn't need that and would enforce it except for when we detect incompatible ts types.

[JoshuaKGoldberg]

Ah, yes, https://typescript-eslint.io/rules/no-useless-default-assignment should be added into the comparisons data. That rule is pretty new and also had a good chunk of bugs filed on it. I'll mark this as blocked on things settlign.

[lishaduck]

Yeah, should probably get #1117 done "soon" (aka in 3 weeks).