.eslintrc.js

const config = {
  parserOptions: {
    ecmaVersion: 2018,
  },
  env: {
    node: true,
  },
  extends: ['eslint:recommended', 'prettier'],
  plugins: ['prettier'],
  rules: {
    'no-confusing-arrow': 'off',
    'no-prototype-builtins': 'off',
    'comma-dangle': [
      'error',
      {
        arrays: 'always-multiline',
        objects: 'always-multiline',
        imports: 'always-multiline',
        exports: 'always-multiline',
        functions: 'never',
      },
    ],
  },
  overrides: [
    {
      files: ['lib/**/*'],
      env: {
        es6: true,
      },
      parserOptions: {
        sourceType: 'module',
      },
    },
    {
      files: ['test/**/*'],
      env: {
        mocha: true,
      },
      parserOptions: {
        sourceType: 'module',
      },
      rules: {
        'no-unused-expressions': 'off',
      },
    },
    {
      files: ['**/*.@(ts|tsx)'],
      parser: '@typescript-eslint/parser',
      plugins: ['@typescript-eslint'],
      parserOptions: {
        sourceType: 'module',
      },
      rules: {
        '@typescript-eslint/consistent-type-assertions': 'error',
        '@typescript-eslint/no-empty-interface': 'error',
        '@typescript-eslint/no-non-null-assertion': 'error',
        '@typescript-eslint/no-redeclare': 'error',
        '@typescript-eslint/type-annotation-spacing': 'error',
        '@typescript-eslint/no-unused-vars': [
          'error',
          {
            argsIgnorePattern: '^_',
            ignoreRestSiblings: true,
          },
        ],
        'no-redeclare': 'off',
      },
    },
    {
      files: ['**/*.d.ts'],
      rules: {
        '@typescript-eslint/no-useless-constructor': 'error',
        'no-var': 'off',
        'no-useless-constructor': 'off',
        'no-redeclare': 'off',
        strict: 'off',
      },
    },
  ],
}

module.exports = config