My personal eslint configuration

When I can choose, I use these JavaScript coding standards in all my projects. It's meant to support (and enforce) the most modern version of JS that is currently natively available (either in browsers or node.js) and is rather strict and explicit, e.g.:

most rules are set to error and errors should never be committed
semicolons, dangling commas and curly brackets are required
some dangerously ambiguous constructs require extra parentheses
const, let and in some situations arrow functions are required
... and more, see base.js for most rules

Example setup

Add a variation of this

	"devDependencies": {
		"eslintrc": "git+https://github.com/NiklasGollenstede/eslintrc.git#<commit>",
		"@typescript-eslint/eslint-plugin": "^5.9.0",
		"ghooks": "^2.0.4"
	},
	"scripts": {
		"lint": "eslintrc --ignore-path .gitignore --ext=.js,.ts ."
	},
	"config": {
		"ghooks": {
			"pre-commit": "npm run lint --silent -- --color"
		}
	},
	"eslintConfig": {
		"extends": "./node_modules/eslintrc/typescript.js",
		"root": true
	}

to the package.json in the project root and optionally delete the package-lock.json there. Then install with npm install and run with npm run lint or use eslint from a terminal or editor. Note that the dependency on @typescript-eslint/eslint-plugin is only required for linting TypeScript with typescript.js, and is due to eslint's strange plugin resolution.

For TypeScript, adding parserOptions.project may be helpful:

	"eslintConfig": {
		"parserOptions": {
			"project": [ "./tsconfig.json" ],
			"extraFileExtensions": [ ".cjs", ".mjs", ".jsm" ]
		}
	}

Environments

base.js: Rather strict rules as the basis for all other configurations.
general.js: Somewhat loosened rules to match all environments fairly well. For locations with mixed scripts, e.g. as a "global" fallback.
node.js: Some additional rules and globals for node.js scripts.
browser.js: Adjustments for a (modern) browser environment. Does not define many global variables.
web-ext.js: meant for WebExtensions. Currently the same as the browser configuration.
typescript.js: For linting TypeScript (and JavaScript).

_utils.js just contains some ... well utilities to write down the rules a bit more clearly.