Browserslist Lint

0.4.0 verified Fri May 01 auth: no javascript

Linter for Browserslist configuration files. Checks target browser queries against popular mistakes like missing 'not dead', ignoring browser diversity, or listing already dead browsers. Stable version 0.4.0, released frequently alongside Browserslist ecosystem. Integrates with CI via CLI or npx. Differentiator: opinionated rules to avoid common footguns when defining browser targets, with online checking at browsersl.ist.

Common errors

error Error: The default export is not available. Use named exports like { lint } instead. ↓

cause Attempted default import after v0.3.0 removed default export.

fix

Change to: import { lint } from 'browserslist-lint'

error Error: The 'path' option must be a string or file descriptor. ↓

cause Passed a config object as 'path' option instead of file path.

fix

Provide the file path string, e.g., { path: '.browserslistrc' }

error Error: Cannot find module 'picocolors' ↓

cause Missing dependency picocolors, which is a peer dependency.

fix

Install peer dependency: npm install picocolors

Warnings

breaking Dropped support for Node.js 14, 16, and 18 in v0.4.0. Requires Node.js >=20. ↓

fix Upgrade Node.js to version 20 or higher.

gotcha Default export removed in v0.3.0 in favor of named exports. ↓

fix Use import { lint } from 'browserslist-lint' instead of default import.

gotcha The lint function expects a 'path' option as string, not a parsed config object. Passing a config object will throw an error. ↓

fix Provide the file path string; to lint a string, use the 'config' option instead.

Install

npm install browserslist-lint

yarn add browserslist-lint

pnpm add browserslist-lint

Imports

lint
wrong
```
import lint from 'browserslist-lint'
```
correct
```
import { lint } from 'browserslist-lint'
```
Function is exported as a named export. Default export is not available since v0.3.

LintOptions

wrong

import { Options } from 'browserslist-lint'

correct

import { LintOptions } from 'browserslist-lint'

TypeScript type for the options parameter. Available as a named export.

LintResult
```
import { LintResult } from 'browserslist-lint'
```
TypeScript type for the result object. Available as a named export.

Quickstart

Shows how to import and use the lint function programmatically with TypeScript, including options and handling warnings.

// install: npm install browserslist-lint
import { lint } from 'browserslist-lint';

async function main() {
  try {
    const result = await lint({
      path: '.browserslistrc', // path to config file
      ignoreMissing: false,    // fail on 'not dead' missing
      ignoreLimited: false,    // fail on limited browser names
    });
    if (result.warnings.length > 0) {
      console.log('Lint warnings:', result.warnings);
    } else {
      console.log('No issues found.');
    }
  } catch (err) {
    console.error('Lint error:', err.message);
  }
}
main();