A subprocess API for WebAssembly programs.
- Supports WASI and Emscripten binaries
- Works in the browser and Node.js
- Async interface (programs run in worker threads)
Compiling and interfacing with WebAssembly programs can be hard. jspawn provides a unified interface and a collection of pre-built binaries.
WARNING: expect breaking/backwards-incompatible changes for MINOR versions before v1.0.0.
npm install --save @jspawn/jspawnindex.mjs
// Or `const { subprocess } = require("@jspawn/jspawn");`
import { subprocess } from "@jspawn/jspawn";
// WASM/binary resolution happens automatically in node when the first argument isn't a path -
// more specifically, it doesn't contain a path-separator and doesn't end with `.wasm`.
const output = await subprocess.run(
// Assumes `@jspawn/imagemagick-wasm` is installed.
// `npm install --save @jspawn/imagemagick-wasm`
"magick",
// Create a blank PNG.
["-size", "100x100", "xc:blue", "blank.png"]
);
console.log(output); // { exitCode: 0, stdout: "", stderr: "" }Run with:
# Depending on your version of node, you may not need the experimental flags.
node --experimental-wasm-bigint --experimental-wasi-unstable-preview1 index.mjsimport { subprocess, fs } from "https://unpkg.com/@jspawn/jspawn/esm/jspawn.mjs";
const output = await subprocess.run(
// Full path to a WASM file - no automatic resolution in the browser.
"https://unpkg.com/@jspawn/imagemagick-wasm/magick.wasm",
// Create a blank PNG.
["-size", "100x100", "xc:blue", "blank.png"]
);
console.log(output); // { exitCode: 0, stdout: "", stderr: "" }
// The file system lives in memory for browser environments.
// Access it using the `fs` module.
const png = await fs.readFileToBlob("blank.png");
// Now, do what you will with the `Blob`.
// Maybe display it.
const img = document.createElement("img");
img.src = URL.createObjectURL(png);
document.body.append(img);