.eslintrc.js

module.exports = {
  env: {
    es6: true,
    node: true
  },
  extends: 'airbnb-base',
  parser: 'babel-eslint',
  parserOptions: {
    ecmaVersion: 2018,
    sourceType: 'module'
  },
  plugins: ['promise'
  ],
  root: true,
  rules: {
    // require parens around arrow function arguments, ex: `(a) => a;`
    'arrow-parens': ['error', 'always'
    ],
    // don't require class methods to call 'this'
    'class-methods-use-this': 0,
    // indent 2 spaces
    indent: ['error',
      2
    ],
    // require unix-style line breaks in the file
    'linebreak-style': ['error', 'unix'
    ],
    // warn about using console statements
    'no-console': ['warn'
    ],
    // strings should use single quotes instead of double
    quotes: ['error', 'single'
    ],
    // always require semi-colons
    semi: ['error', 'always'
    ],
    // require curly braces at all times
    curly: 2,
    // must call `super()` before using this in a class constructor when the
    // class extends another
    'no-this-before-super': 2,
    // require spaces around arrow when making arrow function
    'arrow-spacing': 2,
    // prefer spread instead of using fn.apply, ex: `Math.max(...[1,2,3])`;
    'prefer-spread': 2,
    // allow useless escape
    'no-useless-escape': 0,
    // don't require spaces around curly braces `{foo}`, not `{ foo }`
    'object-curly-spacing': [
      2, 'never'
    ],
    // warning (1) when throwing literal string
    'no-throw-literal': 1,
    // don't allow using functions before them being defined (don't rely on hoisting).
    'no-use-before-define': 0,
    // don't worry about arrow body style for functions.
    'arrow-body-style': 0,
    // 2 rules that have no definition?
    'no-global-assign': 0,
    'no-unsafe-negation': 0,
    // functions/objects being `new`ed need to be uppercase, ex: `let f = new Thing()`
    'new-cap': [
      2,
      { newIsCap: true, capIsNew: false
      },
    ],
    // don't allow unused variables/params unless they are prefixed with 2 underscores
    'no-unused-vars': [
      2,
      { args: 'all', argsIgnorePattern: '^__', varsIgnorePattern: '^__'
      },
    ],
  },
};