.eslintrc.json

/**
 * Linting rules extend and modify the Airbnb style guide.
 * See: https://github.com/airbnb/javascript
 */

{
    "extends": "airbnb-base",
    "plugins": ["import"],
    "env": {
        "es6": true,
        "mocha": true,
        "node": true
    },
    "rules": {
        "array-bracket-spacing": ["off"], // Requires a missing option for my preferred style.
        "arrow-parens": ["error", "as-needed"],
        "comma-dangle": ["error", {
            "arrays": "never", // Supports comma-first rule with multiline arrays.
            "objects": "always-multiline",
            "imports": "always-multiline",
            "exports": "always-multiline",
            "functions": "never"
        }],
        "comma-style": ["error", "last", { "exceptions": { "ArrayExpression": true } }],
        "default-param-last": ["warn"], // Requires substantial code restructuring.
        "func-names": ["error", "as-needed"],
        "func-style": ["warn", "declaration", { "allowArrowFunctions": true }],
        "indent": ["off"], // Requires a missing option for my preferred style.
        "no-bitwise": ["error", { "allow": ["~"] }],
        "no-else-return": ["error", { "allowElseIf": true }],
        "no-multiple-empty-lines": ["error", {"max": 2}],
        "no-nested-ternary": ["off"], // Requires a missing option for my preferred style.
        "no-param-reassign": ["error", { "props": false }],
        "no-plusplus": ["error", { "allowForLoopAfterthoughts": true }],
        "no-underscore-dangle": ["off"],
        "no-undef": ["warn"],
        "no-unused-vars": ["error", {
            "args": "after-used",
            "argsIgnorePattern" : "^_$",
            "vars": "all",
            "ignoreRestSiblings": true
        }],
        "no-use-before-define": ["error", {
            "functions": false,
            "classes": true,
            "variables": true
        }],
        "object-shorthand": ["error", "properties", {
            "avoidQuotes": true
        }],
        "operator-linebreak": ["off"],
        "prefer-const": ["error", { "destructuring": "all", "ignoreReadBeforeAssign": true }],
        "spaced-comment": ["error", "always", {
            "line": {
                "exceptions": ["-", "+", "/"],
                "markers": ["=", "!"] // space here to support sprockets directives
            },
            "block": {
                "exceptions": ["-", "+"],
                "markers": ["=", "!"], // space here to support sprockets directives
                "balanced": true
            }
        }],
        "import/exports-last": ["error"],
        "import/newline-after-import": ["error", { "count": 2 }],
        "import/no-named-as-default": ["warn"],
        "import/order": ["error", { "newlines-between": "never" }],
        "import/prefer-default-export": ["off"]
    }
}