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NodeJS and NPM modules

With rollup.js, we can run CommonJS (CJS) and NodeJS (NPM) modules in WasmEdge too.


See here

Run the example

The simple_common_js_demo/npm_main.js demo shows how it works.

First, you will need to use the NPM command to roll up the dependency modules into a single JavaScript file.

cd example_js/simple_common_js_demo
npm install
npm run build
# Go back to the working directory
cd ../../

NPM generates a new JavaScript file at example_js/simple_common_js_demo/dist/npm_main.mjs, which is the file you can execute with the WasmEdge QuickJS runtime.

$ wasmedge --dir .:. wasmedge_quickjs.wasm example_js/simple_common_js_demo/dist/npm_main.mjs
md5(message)= 78e731027d8fd50ed642340b7c9a63b3
sqrt(-4)= 2i

Code explanation

The simple_common_js_demo/npm_main.js utilizes the third-party md5 and mathjs modules.

const md5 = require('md5');
console.log('md5(message)=', md5('message'));

const { sqrt } = require('mathjs');
console.log('sqrt(-4)=', sqrt(-4).toString());

To run it, we must first use the rollup.js tool to build all dependencies into a single file. In the process, rollup.js converts CommonJS modules into WasmEdge-compatible ES6 modules. The build script is rollup.config.js.

const { babel } = require('@rollup/plugin-babel');
const nodeResolve = require('@rollup/plugin-node-resolve');
const commonjs = require('@rollup/plugin-commonjs');
const replace = require('@rollup/plugin-replace');

const globals = require('rollup-plugin-node-globals');
const builtins = require('rollup-plugin-node-builtins');
const plugin_async = require('rollup-plugin-async');

const babelOptions = {
presets: ['@babel/preset-react'],

module.exports = [
input: './npm_main.js',
output: {
inlineDynamicImports: true,
file: 'dist/npm_main.mjs',
format: 'esm',
external: ['process', 'wasi_net', 'std'],
plugins: [
commonjs({ ignoreDynamicRequires: false }),
'process.env.NODE_ENV': JSON.stringify('production'),
'process.env.NODE_DEBUG': JSON.stringify(''),

The package.json file specifies the rollup.js dependencies and the command to build the npm_main.js demo program into a single bundle.

"dependencies": {
"mathjs": "^9.5.1",
"md5": "^2.3.0"
"devDependencies": {
"@babel/core": "^7.16.5",
"@babel/preset-env": "^7.16.5",
"@babel/preset-react": "^7.16.5",
"@rollup/plugin-babel": "^5.3.0",
"@rollup/plugin-commonjs": "^21.0.1",
"@rollup/plugin-node-resolve": "^7.1.3",
"@rollup/plugin-replace": "^3.0.0",
"rollup": "^2.60.1",
"rollup-plugin-babel": "^4.4.0",
"rollup-plugin-node-builtins": "^2.1.2",
"rollup-plugin-node-globals": "^1.4.0",
"rollup-plugin-async": "^1.2.0"
"scripts": {
"build": "rollup -c rollup.config.js"

Run the following NPM commands to build npm_main.js demo program into dist/npm_main.mjs.

npm install
npm run build

You can import and run any NPM packages in WasmEdge this way.