eslint.config.js

/*
👋 Hi! This ESLint configuration contains a lot more stuff than many repos'!
You can read from it to see all sorts of linting goodness, but don't worry -
it's not something you need to exhaustively understand immediately. 💙

If you're interested in learning more, see the 'getting started' docs on:
- ESLint: https://eslint.org
- typescript-eslint: https://typescript-eslint.io
*/

import eslint from "@eslint/js";
import comments from "@eslint-community/eslint-plugin-eslint-comments/configs";
import jsdoc from "eslint-plugin-jsdoc";
import jsonc from "eslint-plugin-jsonc";
import markdown from "eslint-plugin-markdown";
import n from "eslint-plugin-n";
import packageJson from "eslint-plugin-package-json/configs/recommended";
import perfectionistNatural from "eslint-plugin-perfectionist/configs/recommended-natural";
import * as regexp from "eslint-plugin-regexp";
import vitest from "eslint-plugin-vitest";
import yml from "eslint-plugin-yml";
import tseslint from "typescript-eslint";

export default tseslint.config(
	{
		ignores: [
			"coverage*",
			"lib",
			"node_modules",
			"pnpm-lock.yaml",
			"**/*.snap",
		],
	},
	{
		linterOptions: {
			reportUnusedDisableDirectives: "error",
		},
	},
	eslint.configs.recommended,
	...jsonc.configs["flat/recommended-with-json"],
	...markdown.configs.recommended,
	...yml.configs["flat/recommended"],
	...yml.configs["flat/prettier"],
	comments.recommended,
	jsdoc.configs["flat/recommended-typescript-error"],
	n.configs["flat/recommended"],
	packageJson,
	perfectionistNatural,
	regexp.configs["flat/recommended"],
	...tseslint.config({
		extends: [
			...tseslint.configs.strictTypeChecked,
			...tseslint.configs.stylisticTypeChecked,
		],
		files: ["**/*.js", "**/*.ts"],
		languageOptions: {
			parserOptions: {
				EXPERIMENTAL_useProjectService: {
					allowDefaultProjectForFiles: ["./*.*s", "eslint.config.js"],
					defaultProject: "./tsconfig.json",
				},
			},
		},
		rules: {
			// These off-by-default rules work well for this repo and we like them on.
			"jsdoc/informative-docs": "error",
			"logical-assignment-operators": [
				"error",
				"always",
				{ enforceForIfStatements: true },
			],
			"operator-assignment": "error",

			// These on-by-default rules don't work well for this repo and we like them off.
			"jsdoc/require-jsdoc": "off",
			"jsdoc/require-param": "off",
			"jsdoc/require-property": "off",
			"jsdoc/require-returns": "off",
			"no-constant-condition": "off",

			// These on-by-default rules work well for this repo if configured
			"@typescript-eslint/no-unnecessary-condition": [
				"error",
				{
					allowConstantLoopConditions: true,
				},
			],
			"@typescript-eslint/no-unused-vars": ["error", { caughtErrors: "all" }],
			"@typescript-eslint/prefer-nullish-coalescing": [
				"error",
				{ ignorePrimitives: true },
			],
			"@typescript-eslint/restrict-template-expressions": [
				"error",
				{ allowBoolean: true, allowNullish: true, allowNumber: true },
			],
			"perfectionist/sort-objects": [
				"error",
				{
					order: "asc",
					"partition-by-comment": true,
					type: "natural",
				},
			],

			// Stylistic concerns that don't interfere with Prettier
			"no-useless-rename": "error",
			"object-shorthand": "error",
		},
	}),
	{
		files: ["*.jsonc"],
		rules: {
			"jsonc/comma-dangle": "off",
			"jsonc/no-comments": "off",
			"jsonc/sort-keys": "error",
		},
	},
	{
		extends: [tseslint.configs.disableTypeChecked],
		files: ["**/*.md/*.ts"],
		rules: {
			"n/no-missing-import": [
				"error",
				{ allowModules: ["create-typescript-app"] },
			],
		},
	},
	{
		files: ["**/*.test.*"],
		languageOptions: {
			globals: vitest.environments.env.globals,
		},
		plugins: { vitest },
		rules: {
			...vitest.configs.recommended.rules,

			// These on-by-default rules aren't useful in test files.
			"@typescript-eslint/no-unsafe-assignment": "off",
			"@typescript-eslint/no-unsafe-call": "off",
		},
	},
	{
		files: ["**/*.{yml,yaml}"],
		rules: {
			"yml/file-extension": ["error", { extension: "yml" }],
			"yml/sort-keys": [
				"error",
				{
					order: { type: "asc" },
					pathPattern: "^.*$",
				},
			],
			"yml/sort-sequence-values": [
				"error",
				{
					order: { type: "asc" },
					pathPattern: "^.*$",
				},
			],
		},
	},
);