Skip to main content

Node.js support

Many existing JavaScript apps use Node.js built-in APIs. To support and reuse these JavaScript apps, we are implementing many Node.JS APIs for WasmEdge QuickJS. The goal is to have unmodified Node.js programs running in WasmEdge QuickJS.

To use Node.js APIs in WasmEdge, you must make the modules directory from wasmedge-quickjs accessible to the WasmEdge Runtime. The most straightforward approach is to clone the wasmedge-quickjs repo and run the Node.js app from the repo's top directory.

# Clone the wasmedge-quickjs
git clone
# Use the wasmedge-quickjs directory as the working directory for modules access
cd wasmedge-quickjs
# Download a released WasmEdge QuickJS runtime
curl -OL
# Copy the nodejs project to the current working directory and run the nodejs app
cp -r /path/to/my_node_app .
wasmedge --dir .:. wasmedge_quickjs.wasm my_node_app/index.js

If you want to run wasmedge from a directory outside the repo, you will need to tell it where to find the modules directory using the --dir option. A typical command will look like this: wasmedge --dir .:. --dir ./modules:/path/to/modules wasmedge_quickjs.wasm app.js

The progress of Node.js support in WasmEdge QuickJS is tracked in this issue. There are two approaches for supporting Node.js APIs in WasmEdge QuickJS.

The JavaScript modules

Some Node.js functions can be implemented in pure JavaScript using the modules approach. For example,

The Rust internal modules

Other Node.js functions must be implemented using the internal_module approach in Rust. There are two reasons for that. First, some Node.js API functions are CPU intensive (e.g., encoding) and is most efficiently implemented in Rust. Second, some Node.js API functions require access to the underlying system (e.g., networking and file system) through native host functions.

Node.js compatibility support in WasmEdge QuickJS is a work in progress. It is an excellent way for new developers to get familiar with WasmEdge QuickJS. Join us!