# @chialab/wds-plugin-legacy

> Transform esm modules served by the web dev server into SystemJS modules for legacy browser compatibility.

Latest version **0.19.1** (published 2026-02-25) · MIT license · 0 weekly downloads

## Install

```sh
npm install @chialab/wds-plugin-legacy
pnpm add @chialab/wds-plugin-legacy
yarn add @chialab/wds-plugin-legacy
bun add @chialab/wds-plugin-legacy
```

## Health

**Score 60/100 (C)** — status: stable.

Positive: has types; esm support; no vulnerabilities; has provenance.

Warnings: low downloads; pre 1.0.

## Facts

| | |
|---|---|
| Version | 0.19.1 |
| Published | 2026-02-25 |
| First published | 2021-05-17 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | ESM + CommonJS |
| Node | >=18 |
| Dependencies | 8 |
| Unpacked size | 12.5 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| Author | Chialab |
| Maintainers | chialab-admin, chialab-developers |
| Keywords | dev-server, plugin, legacy, babel |

## Links

- npm: https://www.npmjs.com/package/@chialab/wds-plugin-legacy
- Repository: https://github.com/chialab/rna
- Homepage: https://github.com/chialab/rna#readme
- Issues: https://github.com/chialab/rna/issues
- npm.io page: https://npm.io/package/@chialab/wds-plugin-legacy

## Dependencies (8)

- [cheerio](https://npm.io/package/cheerio.md) ^1.0.0
- [systemjs](https://npm.io/package/systemjs.md) ^6.9.0
- [@babel/core](https://npm.io/package/@babel/core.md) ^7.14.2
- [@babel/preset-env](https://npm.io/package/@babel/preset-env.md) ^7.14.2
- [regenerator-runtime](https://npm.io/package/regenerator-runtime.md) ^0.14.0
- [browserslist-useragent](https://npm.io/package/browserslist-useragent.md) ^4.0.0
- [@chialab/wds-plugin-polyfill](https://npm.io/package/@chialab/wds-plugin-polyfill.md) ^0.19.1
- [@chialab/wds-plugin-node-resolve](https://npm.io/package/@chialab/wds-plugin-node-resolve.md) ^0.19.1

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## Recent versions

- 0.19.1 (latest) — 2026-02-25
- 0.19.0-beta.1 (beta) — 2024-11-04
- 0.18.0-alpha.1 (alpha) — 2023-08-29
- 0.19.0 — 2025-08-25
- 0.19.0-beta.0 — 2024-03-11
- 0.18.0 — 2024-01-11
- 0.18.0-alpha.0 — 2023-05-01
- 0.17.0 — 2022-08-23
- 0.16.4 — 2022-07-10
- 0.16.3 — 2022-07-10
- 0.16.2 — 2022-07-07
- 0.16.1 — 2022-06-08
- 0.16.0 — 2022-06-08
- 0.15.28 — 2022-05-10
- 0.15.17 — 2022-05-02
- … 36 more at https://npm.io/package/@chialab/wds-plugin-legacy/versions

## README

# Wds Plugin Legacy

Transform esm modules served by the <a href="https://modern-web.dev/docs/dev-server/overview/">Web Dev Server</a> into SystemJS modules for legacy browser compatibility.

> [!CAUTION]
> Since we are moving away from the RNA cli, we are discontinuing the development of Web Dev Server plugins.

[![NPM](https://img.shields.io/npm/v/@chialab/wds-plugin-legacy.svg)](https://www.npmjs.com/package/@chialab/wds-plugin-legacy)

## Install

```sh
npm i @chialab/wds-plugin-legacy -D
```

```sh
yarn add @chialab/wds-plugin-legacy -D
```

```sh
pnpm add @chialab/wds-plugin-legacy -D
```

## Usage

```js
import { legacyPlugin } from '@chialab/wds-plugin-legacy';
import { startDevServer } from '@web/dev-server';

await startDevServer({
    plugins: [legacyPlugin()],
});
```

This is similar to the [official legacy plugin](https://www.npmjs.com/package/@web/dev-server-legacy), but with a different polyfill strategy.

## License

**Wds Plugin Legacy** is released under the [MIT](https://github.com/chialab/rna/blob/main/packages/wds-plugin-legacy/LICENSE) license.

---
_Source: https://npm.io/package/@chialab/wds-plugin-legacy · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._