.eslintrc.json

{
  // https://standardjs.com/
  "extends": "standard",

  "env": {
    "browser": true
  },

  // These are known global variables we reference. By default, any reference
  // to an undeclared variable causes a warning. These overrides that warning
  // because we know what we are doing with these.
  // https://eslint.org/docs/user-guide/configuring#specifying-globals
  "globals": {
    // Please keep this list alphabetized.
    "$": false,
    "Romo": false,
    "RomoConfig": false,
    "RomoEnv": false
  },

  // These are overrides to StandardJS rules.
  "rules": {
    // This enforces using `===` and `!==` except for comparing two literal
    // values, evaluating the value of typeof, and comparing against null
    // https://eslint.org/docs/rules/eqeqeq
    // if (foo === true) {}
    // if (foo == null) {} // allows for checking both null/undefined at once
    // if (typeof foo == 'undefined') {}
    "comma-dangle": ["error", {
      "arrays": "always-multiline",
      "objects": "always-multiline",
      "imports": "always-multiline",
      "exports": "always-multiline",
      "functions": "only-multiline"
    }],

    // This enforces using `===` and `!==` except for comparing two literal
    // values, evaluating the value of typeof, and comparing against null
    // https://eslint.org/docs/rules/eqeqeq
    // if (foo === true) {}
    // if (foo == null) {} // allows for checking both null/undefined at once
    // if (typeof foo == 'undefined') {}
    "eqeqeq": ["error", "smart"],

    "key-spacing": ["error", {
      "mode": "minimum",
      "align": "value"
    }],

    // This rule enforces a maximum line length to increase code readability
    // and maintainability. The length of a line is defined as the number of
    // Unicode characters in the line.
    "max-len": ["error", {
      "code": 100, // prefer 80 or less, but fail on more than 100
      "ignoreUrls": true, // ignores lines that contain  a URL
      "ignoreTemplateLiterals": true, // ignores lines that contain a literal
      "ignoreRegExpLiterals": true // ignores lines that contain a RegExp
    }],

    // This is good by default except when you are doing meta-programming and
    // you have a dynamic class stored as a variable or returned from a
    // function. This should be rare outside of code that touches 3rd-party
    // libraries or our internal libraries. We should avoid this in our
    // standard feature code. Therefore, as libraries need to use a technique
    // like this, we can call it out here.
    // https://eslint.org/docs/rules/new-cap
    "new-cap": ["error", {
      "newIsCapExceptions": [
        // Please keep this list alphabetized.
        "popoverOwnerClass",
        "this.class" // `this.class` is always a constructor for Romo-defined objects
      ]
    }],

    // Allow creating instances of objects and not keeping a reference to them.
    // Since we are OO developers we like creating objects to encapsulate
    // state and behavior. Many times that object is autonomous, not needing
    // any further interaction from the thing that created it.
    // https://eslint.org/docs/rules/no-new
    "no-new": ["off"],

    // Too many false-positives
    "no-useless-escape": ["off"],

    // This keeps function definitions looking more like they do in Ruby.
    // https://eslint.org/docs/rules/space-before-function-paren
    // var foo = function(x) {}
    // var foo = async (x) => 1
    "space-before-function-paren": ["error", {
      "anonymous": "never",
      "named": "never",
      "asyncArrow": "always"
    }]
  }
}