npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2026 – Pkg Stats / Ryan Hefner

rollup-plugin-jco

v1.1.0

Published

Rollup plugin for generating bindings from WebAssembly System Interface (WASI) Components

Readme

rollup-plugin-jco

✨ Leverage WASI Components by simply importing them into your project! ✨

  • 🤖 Automatically transpile WebAssembly component bindings to JavaScript
  • 🌳 Automatically generate TypeScript types from WIT definitions
  • ⚡️ Lazy instantiation support
  • 💻 Rollup and Vite support

A plugin for Rollup and Vite that allows you to easily import WebAssembly (WASI) components into your JavaScript or Typescript codebase. It is based on @bytecodealliance/jco, which allows transpiling WASI Components to JavaScript modules.

Installation

To install the plugin, you can use npm or yarn. Make sure you have @bytecodealliance/jco installed in your project; this plugin requires it as a peer-dependency.

npm install --save-dev rollup-plugin-jco @bytecodealliance/jco

Usage

The plugin can be used in your Rollup or Vite configuration file to transpile a WASI component to a JavaScript module. It will automatically handle the transpilation process and generate the necessary bindings for you.

Here's how to initialize the plugin with Rollup and/or Vite:

// vite.config.js
import { defineConfig } from 'vite';
import { wasi } from 'rollup-plugin-jco';

export default defineConfig({
  // ... your vite config ...
  plugins: [
    wasi({/* Extra jco options*/})
  ]
});
// rollup.config.js
import { wasi } from 'rollup-plugin-jco';

export default {
  // ... your rollup config ...
  plugins: [
      wasi({/* Extra jco options*/})
  ]
};

Then, you can import a WebAssembly Component directly in your JS/TS code. Any additional JCO transpilation options can be passed directly in the import statement as query parameters.

[!NOTE] Type generation occurs upon build. When importing a component for the first time, you can expect your IDE to show an error until you build your project next.

import component from './adder_component.wasm?component';

// Typescript types will automatically be generated after first build
const result = component.addTwoIntegers(1, 2);

Full Example

For a full example of how the plugin can be used in a React + Vite project, see the included example in the example directory:

API Reference

Full API reference for the plugin is generated using typedoc and can be found here.

Information relating to the JCO API can be found here or on the JCO GitHub repository.