# @napi-rs/wasm-runtime
> Runtime and polyfill for wasm targets
Latest version **1.2.4** (published 2026-09-10) · MIT license · 0 weekly downloads
## Install
```sh
npm install @napi-rs/wasm-runtime
pnpm add @napi-rs/wasm-runtime
yarn add @napi-rs/wasm-runtime
bun add @napi-rs/wasm-runtime
```
## Health
**Score 65/100 (B)** — status: active.
Positive: esm support; no vulnerabilities; has provenance; recently updated; high maintenance score.
Warnings: low downloads; no types.
## Facts
| | |
|---|---|
| Version | 1.2.4 |
| Published | 2026-09-10 |
| First published | 2024-01-16 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | none |
| Module format | ESM |
| Node | ^20.19.0 \|\| ^22.13.0 \|\| >=23.5.0 |
| Dependencies | 1 |
| Unpacked size | 761.5 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| GitHub stars | 7939 |
| Author | LongYinan |
| Maintainers | broooooklyn, forehalo |
## Links
- npm: https://www.npmjs.com/package/@napi-rs/wasm-runtime
- Repository: https://github.com/napi-rs/napi-rs
- Homepage: https://napi.rs/
- Issues: https://github.com/napi-rs/napi-rs/issues
- Funding: https://github.com/sponsors/Brooooooklyn
- npm.io page: https://npm.io/package/@napi-rs/wasm-runtime
## Dependencies (1)
- [@tybys/wasm-util](https://npm.io/package/@tybys/wasm-util.md) ^0.10.3
## Recent versions
- 1.2.4 (latest) — 2026-09-10
- 1.2.3 — 2026-08-12
- 1.2.2 — 2026-07-31
- 1.2.1 — 2026-07-30
- 1.2.0 — 2026-07-28
- 1.1.6 — 2026-06-24
- 1.1.5 — 2026-06-10
- 1.1.4 — 2026-04-15
- 1.1.3 — 2026-04-08
- 1.1.2 — 2026-03-28
- 1.1.1 — 2025-12-30
- 1.1.0 — 2025-12-02
- 1.0.7 — 2025-10-10
- 1.0.6 — 2025-10-03
- 1.0.5 — 2025-09-13
- … 21 more at https://npm.io/package/@napi-rs/wasm-runtime/versions
## README
# napi-rs
> This project was initialized from [xray](https://github.com/atom/xray)
A framework for building compiled `Node.js` add-ons in `Rust` via Node-API. Website: https://napi.rs
## Sponsors
## Platform Support
[](https://github.com/napi-rs/napi-rs/actions/workflows/test-release.yaml)
[](https://github.com/napi-rs/napi-rs/actions/workflows/asan.yml)
[](https://github.com/napi-rs/napi-rs/actions/workflows/memory-test.yml)
## MSRV
**Rust** `1.88.0`
| | node12 | node14 | node16 | node18 | node20 | node22 |
| --------------------- | ------ | ------ | ------ | ------ | ------ | ------ |
| Windows x64 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Windows x86 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Windows arm64 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| macOS x64 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| macOS aarch64 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Linux x64 gnu | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Linux x64 musl | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Linux aarch64 gnu | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Linux aarch64 musl | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Linux arm gnueabihf | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Linux arm muslebihf | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Linux powerpc64le gnu | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Linux s390x gnu | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Linux loong64 gnu | N/A | N/A | N/A | ✓ | ✓ | ✓ |
| Linux riscv64 gnu | N/A | N/A | ✓ | ✓ | ✓ | ✓ |
| Linux aarch64 android | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Linux armv7 android | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| FreeBSD x64 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
This library depends on Node-API and requires `Node@10.0.0` or later.
We already have some packages written by `napi-rs`: [node-rs](https://github.com/napi-rs/node-rs)
One nice feature is that this crate allows you to build add-ons purely with the `Rust/JavaScript` toolchain and without involving `node-gyp`.
## Taste
> You can start from [package-template](https://github.com/napi-rs/package-template) to play with `napi-rs`
### Define JavaScript functions
```rust
use napi::bindgen_prelude::*;
use napi_derive::napi;
/// module registration is done by the runtime, no need to explicitly do it now.
#[napi]
pub fn fibonacci(n: u32) -> u32 {
match n {
1 | 2 => 1,
_ => fibonacci(n - 1) + fibonacci(n - 2),
}
}
/// use `Fn`, `FnMut` or `FnOnce` traits to defined JavaScript callbacks
/// the return type of callbacks can only be `Result`.
#[napi]
pub fn get_cwd Result<()>>(callback: T) {
callback(
std::env::current_dir()
.unwrap()
.to_string_lossy()
.to_string(),
)
.unwrap();
}
/// or, define the callback signature in where clause
#[napi]
pub fn test_callback(callback: T) -> Result<()>
where
T: Fn(String) -> Result<()>,
{
callback(std::env::current_dir()?.to_string_lossy().to_string())
}
/// async fn, require `async` feature enabled.
/// [dependencies]
/// napi = {version="2", features=["async"]}
#[napi]
pub async fn read_file_async(path: String) -> Result {
Ok(tokio::fs::read(path).await?.into())
}
```
more examples at [examples](./examples/napi)
## Building
This repository is a `Cargo` crate. Any napi-based add-on should contain `Cargo.toml` to make it a Cargo crate.
In your `Cargo.toml` you need to set the `crate-type` to `"cdylib"` so that cargo builds a C-style shared library that can be dynamically loaded by the Node executable. You'll also need to add this crate as a dependency.
```toml
[package]
name = "awesome"
[lib]
crate-type = ["cdylib"]
[dependencies]
napi = "3"
napi-derive = "3"
[build-dependencies]
napi-build = "1"
```
And create `build.rs` in your own project:
```rust
// build.rs
extern crate napi_build;
fn main() {
napi_build::setup();
}
```
So far, the `napi` build script has only been tested on `macOS` `Linux` `Windows x64 MSVC` and `FreeBSD`.
Install `@napi-rs/cli` as a local development dependency to build the Rust crate and copy its dynamic library to a loadable `.node` file.
```js
{
"name": "awesome-package",
"devDependencies": {
"@napi-rs/cli": "^3.0.0"
},
"napi": {
"binaryName": "jarvis"
},
"scripts": {
"build": "napi build --release",
"build:debug": "napi build"
}
}
```
Then you can require your native binding:
```js
require('./jarvis.node')
```
The `module_name` would be your `package` name in your `Cargo.toml`.
`xxx => ./xxx.node`
`xxx-yyy => ./xxx_yyy.node`
You can also copy `Dynamic lib` file to an appointed location:
```bash
napi build [--release] ./dll
napi build [--release] ./artifacts
```
There are [documents](./cli) which contains more details about the `@napi-rs/cli` usage.
## Testing
Because libraries that depend on this crate must be loaded into a Node executable in order to resolve symbols, all tests are written in JavaScript in the `test_module` subdirectory.
To run tests:
```sh
yarn build:test
yarn test
```
## Related projects
- [neon](https://www.neon-bindings.com)
- [node-bindgen](https://github.com/infinyon/node-bindgen)
## Features table
| Rust Type | Node Type | [NAPI Version](https://nodejs.org/api/n-api.html#n_api_node_api_version_matrix) | Minimal Node version | Enable by `napi` feature |
| ------------------------ | ------------------- | ------------------------------------------------------------------------------- | -------------------- | ------------------------ |
| u32 | Number | 1 | v8.0.0 |
| i32/i64 | Number | 1 | v8.0.0 |
| f64 | Number | 1 | v8.0.0 |
| bool | Boolean | 1 | v8.0.0 |
| String/&'a str | String | 1 | v8.0.0 |
| OsString/&'a OsStr | String | 1 | v8.0.0 |
| PathBuf/&'a Path | String | 1 | v8.0.0 |
| Latin1String | String | 1 | v8.0.0 | latin1 |
| UTF16String | String | 1 | v8.0.0 |
| Object | Object | 1 | v8.0.0 |
| serde_json::Map | Object | 1 | v8.0.0 | serde-json |
| serde_json::Value | any | 1 | v8.0.0 | serde-json |
| Array | Array | 1 | v8.0.0 |
| Vec | Array | 1 | v8.0.0 |
| Buffer | Buffer | 1 | v8.0.0 |
| External | External | 1 | v8.0.0 | |
| Null | null | 1 | v8.0.0 |
| Undefined/() | undefined | 1 | v8.0.0 |
| Result<()> | Error | 1 | v8.0.0 |
| T: Fn(...) -> Result | Function | 1 | v8.0.0 |
| Async/Future | Promise | 4 | v10.6.0 | async |
| AsyncTask | Promise | 1 | v8.5.0 |
| JsGlobal | global | 1 | v8.0.0 |
| JsSymbol | Symbol | 1 | v8.0.0 |
| Int8Array/Uint8Array ... | TypedArray | 1 | v8.0.0 |
| JsFunction | threadsafe function | 4 | v10.6.0 | napi4 |
| BigInt | BigInt | 6 | v10.7.0 | napi6 |
---
_Source: https://npm.io/package/@napi-rs/wasm-runtime · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._