eslint-config-loopback

14.0.0 verified Sat Apr 25 auth: no javascript

Shareable ESLint configuration for LoopBack projects. Version 14.0.0 provides a set of predefined rules consistent with LoopBack's coding standards. This package is maintained by the LoopBack team and is primarily used in Node.js server-side applications. It integrates with ESLint and allows easy extension and overriding of rules. Release cadence is tied to LoopBack releases. Unlike generic ESLint configs, this one is tailored specifically for LoopBack projects, ensuring code style consistency across the ecosystem.

Common errors

error Error: Failed to load config 'loopback' to extend from. ↓

cause The package is not installed or ESLint cannot find the config module.

fix

Ensure eslint-config-loopback is installed: npm install -D eslint eslint-config-loopback.

error Definition for rule 'comma-dangle' was not found. ↓

cause The rule 'comma-dangle' is deprecated or removed in the version of ESLint in use.

fix

Update .eslintrc to use the correct rule name (e.g., '@stylistic/comma-dangle') or set to 'off'.

error Environment key "es2021" is unknown. ↓

cause ESLint version does not support the specified ecmaVersion or env setting.

fix

Use appropriate ESLint version or adjust ecmaVersion/env in .eslintrc.

Warnings

breaking ESLint version compatibility: eslint-config-loopback may require specific ESLint major versions. Breaking changes in ESLint (e.g., v7 to v8) can cause config incompatibility. ↓

fix Check peer dependency requirements in package.json; use compatible ESLint version.

deprecated Some rules may be deprecated in newer ESLint versions (e.g., no-catch-shadow, no-native-reassign). These rules are no longer valid and can cause errors. ↓

fix Override deprecated rules in .eslintrc with appropriate replacements or set to 'off'.

gotcha The config extends 'loopback' but does not include a 'parser' option. If using TypeScript or Babel, you must set a parser manually. ↓

fix Add 'parser' field to .eslintrc (e.g., '@typescript-eslint/parser') and install corresponding packages.

gotcha Config does not include environment settings (e.g., node, browser). You may need to set 'env' in your .eslintrc for proper global variable recognition. ↓

fix Add 'env' object to .eslintrc: { "env": { "node": true } }.

Install

npm install eslint-config-loopback

yarn add eslint-config-loopback

pnpm add eslint-config-loopback

Imports

eslintConfig
wrong
```
import eslintConfig from 'eslint-config-loopback'
```
correct
```
module.exports = { extends: 'loopback' }
```
The package is not a JavaScript module to import; it's an ESLint config referenced by string name in .eslintrc or eslintConfig in package.json. Since v8, ESLint requires the config to be referenced by name or via a config file.
extends
wrong
```
{
  "extends": ["loopback"]
}
```
correct
```
{
  "extends": "loopback"
}
```
While using an array is valid, the typical usage is a simple string. Both work, but string is the recommended pattern per LoopBack docs.
parserOptions
wrong
```
{
  "extends": "loopback",
  "parser": "babel-eslint"
}
```
correct
```
{
  "extends": "loopback",
  "parserOptions": { "ecmaVersion": 2021 }
}
```
The config does not specify parser options; you may override them. Avoid using babel-eslint unless transpiling, as LoopBack expects standard ESLint parser.

Quickstart

Shows how to install and configure eslint-config-loopback in a LoopBack project, with optional override of rules.

// Install dependencies
// npm install -D eslint eslint-config-loopback

// .eslintrc
{
  "extends": "loopback",
  "rules": {
    "comma-dangle": "off"
  }
}

// package.json scripts
{
  "scripts": {
    "lint": "eslint .",
    "posttest": "npm run lint"
  }
}

// Run lint
// npm run lint