@nexso/eslint-config

A extension of eslint-config-airbnb-base style but for newer javascript (ES2021). Used in the nexso development (an aPaaS).

This is intended to work in Node.js 14+ environments.

How to use

Install the config as development dependency npm i -D eslint @nexso/eslint-config.

Create a .eslintrc file with:

{
  "extends": "@nexso",
  "rules": [
  ]
}

Add type module to your package.json file:

{
  "type": "module",
  "name": "your-app-or-lib-name",
  "version": "1.0.0",
}

Using with eslint wizard (optional)

If you want to use with eslint --init command, simple change the file:

• Windows (Global installation): %APPDATA%\npm\node_modules\eslint\lib\init\config-initializer.js

• Linux: /usr/local/lib/node_modules/eslint/lib/init/config-initializer.js

And find the question: name: "styleguide" (~ line 540) and add nexso option:

{
    type: "select",
    name: "styleguide",
    message: "Which style guide do you want to follow?",
    choices: [
        { message: "nexso: https://github.com/nexsodev/eslint-config", name: "@nexso/eslint-config" }, // This
        { message: "Airbnb: https://github.com/airbnb/javascript", name: "airbnb" },
        { message: "Standard: https://github.com/standard/standard", name: "standard" },
        { message: "Google: https://github.com/google/eslint-config-google", name: "google" },
        { message: "XO: https://github.com/xojs/eslint-config-xo", name: "xo" }
    ],

You can also use the file from this repo: config-initializer.js.

Secure by default

This config also includes security plugins:

• eslint-plugin-security
• @microsoft/eslint-plugin-sdl

Differences from AirBnb Base

Some configs from airbnb-base was changed:

module imports

Use ES6 syntax to import modules, natively in node.js 14+.

// import npm or node built-in modules (old: `require()`)
import { createPrivateKey, createPublicKey } from 'crypto';

// Whatever ...
function getKeyPair(pem) {
  return {
    public: createPublicKey(pem),
    private: createPrivateKey(pem),
  }
}

// export class, function, module, lib... (old `module.exports`)
export default getKeyPair;

Note that you must add type: module to your package.json file:

{
  "type": "module",
  "name": "your-application",
  "version": "1.0.0",
  "main": "index.js"
}

So the source type is set to module:

"parserOptions": {
    "sourceType": "module"
}

Import extensions

Node.js type module requires that you specify the extension when importing a local file:

// src/controller/foo.js
import { Bar } from '../svc/index.js'; // index must be declared too

So the rule import/extensions is set as:

"import/extensions": ["error", "always", {
    "ignorePackages": true
}]

Private fields/methods

Enable private fields and private methods:

For this work in VS Code, Babel parser should be used and two plugins are used:

"parser": "@babel/eslint-parser",
"parserOptions": {
    "ecmaVersion": 12,
    "babelOptions": {
        "plugins": [
            "@babel/plugin-proposal-class-properties",
            "@babel/plugin-proposal-private-methods"
        ]
    }
},

for await...of

AirBnB config doesn't support this statement and thrown an error:

iterators/generators require regenerator-runtime, which is too heavyweight for this guide to allow them. Separately, loops should be avoided in favor of array iterations.

You can read the discussion at Issue #1271.

This config enables this with the rules:

"no-restricted-syntax": [
    "error",
    {
        "selector": "ForInStatement",
        "message": "for..in loops iterate over the entire prototype chain, which is virtually never what you want. Use Object.{keys,values,entries}, and iterate over the resulting array."
    },
    {
        "selector": "LabeledStatement",
        "message": "Labels are a form of GOTO; using them makes code confusing and hard to maintain and understand."
    },
    {
        "selector": "WithStatement",
        "message": "`with` is disallowed in strict mode because it makes code impossible to predict and optimize."
    }
]

Note the absence of ForOfStatement selector. (Since we don't have specific AST for for await...of).

max-len in JSDoc comments

Ignore max-len in comments to not warn about long JS Docs lines in pure JavaScript.

  /**
   * To something that requires a long type param
   *
   * @param {import('@google-cloud/secret-manager').protos.google.cloud.secretmanager.v1.SecretVersion} secret The secret payload
   */

So the rule import/extensions is set as:

"max-len": [
    "error",
    { 
        "code": 100,
        "ignoreComments": true 
    }
]

Version history

See CHANGELOG