Registry / web-framework / lit-swc-transpiler

lit-swc-transpiler

library1.0.0jsnpmunverified

A fast SWC-based transpiler for LitElement and other custom elements. Version 1.0.0 focuses on converting decorator and template syntax to standard JavaScript with minimal overhead. Ships TypeScript types for better DX. Compared to Babel-based alternatives, it leverages SWC's Rust core for up to 20x faster compilation. Ideal for large web component projects and build pipelines. Currently in early release, no stable release cadence yet.

web-framework

npm install lit-swc-transpiler

package ↗

INSTALL

IMPORT

SIG · LIT-SWC-TRANSPILER

lit-swc-transpiler

web-frameworkjavascriptv1.0.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

transpile

✓ import { transpile } from 'lit-swc-transpiler'

✗ const { transpile } = require('lit-swc-transpiler')

Library is ESM-only; CommonJS require is not supported.

TransformOptions

✓ import type { TransformOptions } from 'lit-swc-transpiler'

✗ import { TransformOptions } from 'lit-swc-transpiler'

Type import only; runtime use will cause error.

transformSync

✓ import { transformSync } from 'lit-swc-transpiler'

Synchronous version of transpile; use only in build scripts.

Shows basic usage: transpile a LitElement with decorators and TypeScript, outputting standard JS.

import { transpile } from 'lit-swc-transpiler'; const code = ` import { LitElement, html, css } from 'lit'; class MyElement extends LitElement { static styles = css\`p { color: red; }\`; @property() name = 'World'; render() { return html\`<p>Hello, \${this.name}!</p>\`; } } customElements.define('my-element', MyElement); `; const result = transpile(code, { filename: 'my-element.ts', decorators: true, ts: true }); console.log(result.code);

Debug

Known issues

breakingDecorator syntax is only supported in TypeScript mode; plain JavaScript files cannot use decorators without a separate parser.

fix

Enable TypeScript mode by setting `ts: true` option, or pre-process with a decorator transformer.

affects: >=1.0.0

deprecatedThe `transform` function is deprecated in favor of `transpile`.

fix

Use `transpile` instead. `transform` will be removed in v2.

affects: >=1.0.0

gotchaThe library does not handle `css` tagged template literal polyfills; ensure Lit's `css` helper is imported.

fix

Add `import { css } from 'lit';` in your source files.

affects: >=1.0.0

gotchaSource maps are not generated by default; enable with `sourceMaps: true` option.

fix

Pass `sourceMaps: true` in options to get inline source maps.

affects: >=1.0.0

Errors

Common errors & fixes

Error: Cannot find module 'lit-swc-transpiler'

Package not installed or wrong import path.

fix

Run `npm install lit-swc-transpiler` and ensure import path is correct.

TypeError: transpile is not a function

Using CommonJS require instead of ESM import.

fix

Change `const { transpile } = require('lit-swc-transpiler')` to `import { transpile } from 'lit-swc-transpiler'`.

SyntaxError: Unexpected token (5:10) - Decorators are not valid here.

Decorator syntax in a file not recognized as TypeScript.

fix

Either rename file to .ts or pass `ts: true` in options.

Upgrade

Version history

1.0.0latest on npm

Audit

Dependencies

@swc/corerequiredCore SWC compiler engine for transpilation

litrequiredRuntime for LitElement decorators and templates

Agent activity

4 hits · last 30 days

node

Resources

packagehttps://www.npmjs.com/package/lit-swc-transpiler ↗