index.js

module.exports = {
	plugins: ["@typescript-eslint", "import"],
	extends: [
		"eslint:recommended",
		"plugin:@typescript-eslint/recommended",
		"plugin:import/errors",
		"plugin:import/warnings",
		"plugin:import/typescript",
		// prettier always need to be last
		"prettier",
	],
	overrides: [
		{
			files: ["**/*.js", "**/*.jsx"],
			rules: {
				// require is allowed in js, as we may not have import available
				"@typescript-eslint/no-var-requires": "off",
			},
		},
		{
			files: ["**/*/*.spec.js", "**/*/*.spec.jsx", "**/*/*.spec.ts", "**/*/*.spec.tsx"],
			plugins: ["jest"],
			extends: [
				"plugin:jest/recommended",
			],
			rules: {
				// enforce describe around "it" blocks
				"jest/require-top-level-describe": "error",
				// acceptable as long as it's only imported from other tests
				"jest/no-export": "warn",
				// the following warning catches errors like
				//   `expect(button.props().href === "/test");`
				// and is thus an error
				"jest/valid-expect": "error",
				// a bad title with e.g. a space at the end is okay, but rather warn
				"jest/valid-title": "warn",
				// we prefer "it" over "test"
				"jest/consistent-test-it": ["warn", { fn: "it" }],
				"jest/prefer-lowercase-title": ["warn", { ignoreTopLevelDescribe: true }],
				"jest/prefer-to-contain": "warn",
				"jest/prefer-to-have-length": "warn",
			},
		},
	],
	rules: {
		"@typescript-eslint/no-explicit-any": "off",
		"@typescript-eslint/explicit-function-return-type": "off",
		"@typescript-eslint/no-empty-interface": "warn",
		"@typescript-eslint/ban-types": [
			"warn",
			{
				types: {
					"{}": {
						message:
							"If you're trying to do something like React.FC<{}>, use React.FC instead",
					},
				},
				extendDefaults: true,
			},
		],
		// non-null assertions aren't great, but sometimes a last resort
		"@typescript-eslint/no-non-null-assertion": "off",
		// redundant types are totally okay, they can signal developer intent
		"@typescript-eslint/no-inferrable-types": "off",
		// these can be acceptable
		"@typescript-eslint/no-empty-function": "off",
		// we're not so strict on external module exports and trust typescript's interference here
		"@typescript-eslint/explicit-module-boundary-types": "off",
		// too noisy for now
		"@typescript-eslint/no-unused-vars": "off",
		// while these aren't great, if someone explicitly uses them let's allow them
		"@typescript-eslint/ban-ts-comment": "off",
		// no case declarations are not necessarily a bug, however they can lead to misused variables
		"no-case-declarations": "warn",
		"no-empty-pattern": "warn",
		// we're pretty lenient on these, and they can help tighten types
		"no-extra-boolean-cast": "off",
		// these are usually not great, but let's not fully forbid them
		"no-constant-condition": "warn",
		// prettier compat
		"no-tabs": ["warn", { allowIndentationTabs: true }],
		// consts are generally preferred in this case
		"prefer-const": "warn",
		// these next for rules are done by typescript anyway, so not required
		"import/named": "off",
		"import/namespace": "off",
		"import/default": "off",
		"import/no-named-as-default-member": "off",
		// these are just too expensive
		"import/no-named-as-default": "off",
		"import/no-cycle": "off",
		"import/no-unused-modules": "off",
		"import/no-deprecated": "off",
		// can't deal with aliases
		"import/no-unresolved": "off",
	},
};