.eslintrc.js

module.exports = {
    root: true,

    extends: [
        'airbnb',
        'plugin:flowtype/recommended',
        'plugin:jest/recommended',
    ],

    plugins: [
        'flowtype',
        'jest',
    ],

    env: {
        'jest': true,
    },

    // overrides the airbnb ruleset
    rules: {
        // 4-space indent
        'indent': ['error', 4, { SwitchCase: 1 }],

        // require space before function opening parenthesis
        'space-before-function-paren': ['error', 'always'],

        // allow console methods
        'no-console': 'off',

        // quote all or no props in an object, disallow mixing
        'quote-props': ['error', 'consistent'],

        // never assign to a fn param, but allow assignment to its props
        'no-param-reassign': ['error', { 'props': false }],

        // allow padded blocks
        'padded-blocks': 'off',

        // enforce braces
        'curly': ['error', 'all'],

        // check that when we import default from our own code, there's a default export
        'import/default': 'error',

        // check that named imports exist in the exports
        'import/named': 'error',

        // check that wildcard imports '* as foo' exist when dereferenced
        'import/namespace': 'error',

        // check that external modules are referenced directly in package.json
        // as dependencies, devDependencies or optionalDependencies.
        'import/no-extraneous-dependencies': ['error', {
            'devDependencies': true,
            'optionalDependencies': true,
        }],

        // disallow use of exported name as name of default import,
        // as it's likely you missed some brackets.
        'import/no-named-as-default': 'error',

        // imports always come first
        'import/imports-first': ['error', ''],

        // disallow use of exported name as property on the default export,
        // as this is likely to confuse.
        'import/no-named-as-default-member': 'error',

        // ensure imports are in a consistent order:
        'import/order': ['error', {
            'groups': ['builtin', 'external', 'internal', 'parent', 'sibling', 'index'],
        }],

        // must separate imports from rest of code
        'import/newline-after-import': 'error',

        // import must include extensions for all files except these
        "import/extensions": [
            "error",
            "always",
            {
                "js": "never",
                "jsx": "never",
                "es": "never"
            }
        ],

        // allow dynamic requires
        "import/no-dynamic-require": 'off',

        // allow 'require' anywhere
        'global-require': 'off',

        'no-underscore-dangle': ['error', {
            'allowAfterThis': false,
            'allow': [
                '__',  // for Ramda's R.__
            ],
        }],

        'no-warning-comments': [
            'warn', {
                'terms': ['::TODO::'],
                'location': 'start',
            }
        ],

        'generator-star-spacing': ['error', { 'before': true, 'after': true }],

        'object-curly-newline': 'off',

        // jsx-a11y has refactored href-no-hash to anchor-is-valid:
        // waiting for eslint-config-airbnb to catch up (out-of-date at v15.1.0)
        'jsx-a11y/href-no-hash': 'off',
    },

    // add as they're encountered
    globals: {
    },
};