.eslintrc.js

module.exports = {
  env: {
    browser: true,
    es6: true,
    jest: true,
  },
  extends: [
    'plugin:@typescript-eslint/recommended',
    'airbnb-base'
  ],
  plugins: ['@typescript-eslint'],
  parser: '@typescript-eslint/parser',
  globals: {
    Atomics: 'readonly',
    SharedArrayBuffer: 'readonly',
  },
  parserOptions: {
    ecmaVersion: 2018,
    sourceType: 'module',
  },
  settings: {
    'import/resolver': {
      node: {
        extensions: ['.js', '.ts'],
      },
    },
  },
  overrides: [
    {
      files: ['*.ts', '*.tsx'],
      rules: {
        'no-dupe-class-members': 'off',
      },
    },
  ],
  rules: {
    '@typescript-eslint/explicit-function-return-type': ['warn', {
      allowTypedFunctionExpressions: true,
      allowExpressions: true,
    }],
    'import/extensions': ['error', 'ignorePackages', {
      js: 'never',
      ts: 'never',
    }],
  }
};