Polymer Linter

3.0.1 verified Fri May 01 auth: no javascript deprecated

Polymer Linter (v3.0.1) is a library for finding suspicious patterns and errors in web projects using Polymer custom elements. It is built on the Polymer Analyzer and provides AST-based linting with high-level feature queries. The linter is typically run via Polymer CLI or integrated into editors like VS Code. It offers rule collections (e.g., polymer-2-hybrid) and individual rules. Release cadence is low, as the project is in maintenance mode. Key differentiators: Polymer-specific linting rules (e.g., attribute checks, behaviors spelling) and tight integration with Polymer toolchain.

Common errors

error Error: Cannot find module 'polymer-analyzer' ↓

cause Missing dependency polymer-analyzer when using polymer-linter programmatically.

fix

npm install polymer-analyzer

error TypeError: linter.lint is not a function ↓

cause Using old v2 API where lint was called differently; v3 lint method expects (document, options).

fix

Update code to: linter.lint(document, { rules: ['polymer-2-hybrid'] })

error Warning: No rules matched; nothing to lint. ↓

cause Specified rule collection name is misspelled or not registered.

fix

Check rule names in registry; use correct string like 'polymer-2-hybrid'.

Warnings

deprecated Polymer Linter is deprecated and no longer maintained. Polymer 3+ does not use this linter. ↓

fix Migrate to lit-analyzer or eslint-plugin-lit for Polymer 3 and LitElement projects.

breaking The API changed significantly from v2 to v3. Linter constructor now requires an Analyzer instance. ↓

fix Instantiate polymer-analyzer and pass it to Linter.

breaking Rule collections are now specified as strings in an array (e.g., ['polymer-2-hybrid']), not as separate arguments. ↓

fix Pass rules as array in options object.

gotcha The linter depends on polymer-analyzer which loads files via URL loader. No built-in file system loader. ↓

fix Provide a custom urlLoader or use polymer-cli to run it.

Install

npm install polymer-linter

yarn add polymer-linter

pnpm add polymer-linter

Imports

Linter

wrong

const Linter = require('polymer-linter').Linter

correct

import { Linter } from 'polymer-linter'

ESM only; named export.

Warning

wrong

const Warning = require('polymer-linter').Warning

correct

import { Warning } from 'polymer-linter'

Named export for warning types.

registry

wrong

import registry from 'polymer-linter'

correct

import { registry } from 'polymer-linter'

Named export for rule registry.

Quickstart

Shows how to programmatically use Polymer Linter: create an Analyzer, instantiate Linter, and lint a document with a rule collection.

import { Linter } from 'polymer-linter';
import { Analyzer } from 'polymer-analyzer';

const analyzer = new Analyzer({ urlLoader: { canLoad: () => false, load: () => '', request: () => '' } });
const linter = new Linter(analyzer);

// See available rules
console.log(linter.registry.rules);

// Create a lint result
const doc = await analyzer.analyze('file.html');
const warnings = await linter.lint(doc, { rules: ['polymer-2-hybrid'] });
for (const warning of warnings) {
  console.log(warning.message);
}