metro-minify-swc

1.0.0-alpha verified Fri May 01 auth: no javascript

A drop-in replacement minifier for Metro bundler that uses SWC (Speedy Web Compiler) for fast JavaScript minification. Version 1.0.0-alpha is experimental and may not be stable. SWC's Rust-based implementation aims to provide better performance than Metro's default minifier. Requires metro >=0.80.0. Provides TypeScript types.

Common errors

error Error: Cannot find module 'metro-minify-swc' ↓

cause Package not installed or not in node_modules.

fix

Run npm install --save-dev metro-minify-swc (or yarn/pnpm equivalent).

error Error: Minifier path not found: metro-minify-swc ↓

cause Metro cannot resolve the minifier module.

fix

Ensure the package is installed and check that metro.config.js uses the correct string for minifierPath.

error TypeError: Cannot read properties of undefined (reading 'compress') ↓

cause minifierConfig is undefined or not an object.

fix

Set minifierConfig to an empty object or a proper configuration object.

Warnings

deprecated Package is 1.0.0-alpha and experimental; API may change without notice. ↓

fix Pin exact version and monitor releases for breaking changes.

gotcha minifierConfig must be an object; passing undefined or null can cause errors. ↓

fix Always provide an empty object if no configuration is needed: minifierConfig: {}.

gotcha Metro's default minifier options are not automatically applied; you must specify all desired options. ↓

fix Explicitly set all minifier options in minifierConfig, including defaults.

gotcha SWC minifier may produce slightly different output than Metro's default (Terser-based) minifier; test thoroughly. ↓

fix Verify bundle behavior in development and production environments.

Install

npm install metro-minify-swc

yarn add metro-minify-swc

pnpm add metro-minify-swc

Imports

default

wrong

import minifier from 'metro-minify-swc';

correct

const minifier = require('metro-minify-swc');

Package uses CommonJS exports; ESM import is not available.

minifier (named)
wrong
```
import { minifier } from 'metro-minify-swc';
```
correct
```
const { minifier } = require('metro-minify-swc');
```
The default export is the minifier function, so destructuring may not work as expected. Prefer default import.
minifierPath in metro.config.js
wrong
```
minifierPath: 'metro-minify-swc/index.js'
```
correct
```
minifierPath: 'metro-minify-swc'
```
Metro resolves the module automatically; specifying an index file is redundant and may cause resolution errors.

Quickstart

Shows how to configure Metro's transformer to use metro-minify-swc with custom compress and mangle options.

// metro.config.js
module.exports = {
  transformer: {
    minifierPath: 'metro-minify-swc',
    minifierConfig: {
      compress: {
        drop_console: true,
        unused: true,
      },
      mangle: {
        toplevel: true,
      },
    },
  },
};