polymer-transpiler

1.1.4-alpha verified Fri May 01 auth: no javascript deprecated

Polymer 1 to Polymer 2 transpiler that converts Polymer function-based elements into ES6 class syntax. Current version is 1.1.4-alpha, released as an unstable alpha with frequent breaking changes. It provides a CLI tool to search and transpile components, allowing customization of base class. Differentiators: specific focus on Polymer 1→2 migration, simple CLI usage, but no other major features or community support.

Common errors

error Cannot find module 'polymer-transpiler' ↓

cause Package not installed globally or missing from node_modules

fix

Run: npm install -g polymer-transpiler

error TypeError: polymerTranspiler.transpile is not a function ↓

cause Incorrect import or using default import as named object

fix

Use: import polymerTranspiler from 'polymer-transpiler' then call polymerTranspiler.transpile()

error Error: The specified path does not contain Polymer components ↓

cause CLI path option points to a directory without Polymer 1 elements

fix

Provide a valid path with .html files containing Polymer({}) calls

Warnings

breaking CLI name changed from 'poly-transpiler' to 'polymer-transpiler' in v1.1.0-alpha ↓

fix Update scripts and references to use 'polymer-transpiler' instead of 'poly-transpiler'

deprecated Polymer itself is deprecated; this transpiler is only relevant for legacy codebases ↓

fix Migrate to modern web component frameworks (Lit, etc.)

gotcha Alpha stability: anything can change, no semver in alpha, may break without notice ↓

fix Pin to a specific version and test thoroughly before using in production

Install

npm install polymer-transpiler

yarn add polymer-transpiler

pnpm add polymer-transpiler

Imports

default

wrong

const polymerTranspiler = require('polymer-transpiler')

correct

import polymerTranspiler from 'polymer-transpiler'

Package is ESM-only, no CommonJS export.

transpile

wrong

const { transpile } = require('polymer-transpiler')

correct

import { transpile } from 'polymer-transpiler'

Named export for programmatic use.

PolymerTranspiler

wrong

import { PolymerTranspiler } from 'polymer-transpiler'

correct

import PolymerTranspiler from 'polymer-transpiler'

Default export is the class.

Quickstart

Transpile a Polymer 1 element string to Polymer 2 class syntax

import polymerTranspiler from 'polymer-transpiler';

// Example: transpile a single Polymer 1 element file
const input = `
  <dom-module id="my-element">
    <template><span>{{text}}</span></template>
    <script>
      Polymer({
        is: 'my-element',
        properties: { text: { type: String } }
      });
    </script>
  </dom-module>
`;

const output = polymerTranspiler.transpile(input, { extends: 'Polymer.Element' });
console.log(output);
// Output will be ES6 class extending Polymer.Element