Custom TypeScript project settings for ESLint and Prettier! A solid baseline ruleset that you can override as desired. Check out the specific settings in .eslintrc.js and .prettierrc.js.

npm install --save-dev @adamhamlin/eslint-config

NOTE: This package uses peer dependencies, so there's no need to explicitly install eslint, prettier, @typescript-eslint/eslint-plugin, etc. (unless you're using NPM version 6.x or earlier).

Your .eslintrc.js file should look like:

module.exports = {
    extends: ['@adamhamlin/eslint-config'],
    rules: {
        // overrides, if desired
    },
    // ...
};

Your .prettierrc.js file should look like:

module.exports = {
    ...require('@adamhamlin/eslint-config/prettier'),
    // overrides, if desired
};

That's it.

I like husky+lint-staged to ensure all committed code is compliant, along with npm run check at some point during CI.

Add the following as desired to your package.json file:

"scripts": {
    "_lint": "eslint --fix",
    "_lint:check": "eslint",
    "_format": " prettier --write --ignore-unknown",
    "_format:check": "prettier --check --ignore-unknown",
    "fix": "npm run _lint . && npm run _format .",
    "check": "npm run _lint:check . && npm run _format:check ."
},
"lint-staged": {
    "*.ts": "npm run _lint -- --cache",
    "*": "npm run _format"
},

This package also bundles eslint-plugin-jest, but it does not configure it. If you're using jest, you probably want to include something like this in your .eslintrc.js:

overrides: [{
    files: ['**/__tests__/**'],
    plugins: ['jest'],
    extends: ['plugin:jest/recommended'],
    rules: {
        // more overrides...
    }
}],

• By default, eslint will ignore *.js files and typical TS output directories (e.g., dist, out). You can override ignorePatterns as needed.
• This package already bundles a parser and sets parserOptions.
• By default, eslint and prettier are kept fully separated. If you would like eslint to also use rules from your prettier config, update the following in .eslintrc.js:

  rules: {
      'prettier/prettier': ['error', require('./.prettierrc')]
  }