swc-loader

0.2.7 verified Sat Apr 25 auth: no javascript

Webpack loader for the SWC compiler (Rust-based transpiler for JS/TS). Current stable version 0.2.7. Released as part of the swc project (monorepo under @swc). Key differentiators: integrates SWC into Webpack build pipeline for fast transpilation; supports both JavaScript and TypeScript via swc configuration; can be run synchronously or asynchronously. Alternatives include babel-loader, ts-loader.

Common errors

error Module not found: Error: Can't resolve '@swc/core' ↓

cause @swc/core not installed

fix

npm install --save-dev @swc/core

error Error: swc-loader is not compatible with webpack < 2 ↓

cause Webpack version too low

fix

Upgrade webpack to >=2

error Error: swc-loader requires sync: true for full error stack ↓

cause Async mode may hide error details

fix

Set sync: true in loader options

Warnings

gotcha Error messages may be truncated. Use sync: true for full error output. ↓

fix Add sync: true to loader options.

breaking swc-loader requires @swc/core ^1.2.147. Incompatible with older versions. ↓

fix Upgrade @swc/core to ^1.2.147.

deprecated Options passed directly to loader are forwarded to swc. Some options changed between swc versions. ↓

fix Refer to swc.rs/docs/configuring-swc for valid options.

gotcha The loader expects .swcrc config file by default. Inline options merge with .swcrc. ↓

fix Either provide .swcrc or pass all config via loader options.

gotcha TypeScript support requires explicit parser syntax: 'typescript' in jsc.parser. ↓

fix Add jsc: { parser: { syntax: 'typescript' } } to loader options.

Install

npm install swc-loader

yarn add swc-loader

pnpm add swc-loader

Imports

swc-loader
wrong
```
import swcLoader from 'swc-loader'
```
correct
```
use: { loader: 'swc-loader' } in webpack config
```
This is a webpack loader, not a programmatic API. Use it in webpack module.rules, not as an import.

Quickstart

Basic webpack configuration to transpile JavaScript files using swc-loader

// webpack.config.js
module.exports = {
  module: {
    rules: [
      {
        test: /\.m?js$/,
        exclude: /node_modules/,
        use: {
          loader: 'swc-loader',
          options: {
            sync: true,
            jsc: {
              parser: {
                syntax: 'ecmascript',
                jsx: false
              },
              target: 'es2020'
            }
          }
        }
      }
    ]
  }
};
// package.json side: ensure @swc/core and webpack are installed
// npm install --save-dev @swc/core swc-loader webpack