@lighttransport/mujoco-wasm

Physics-only MuJoCo WebAssembly bindings for JavaScript and TypeScript.

This package contains the minimal mujoco_physics Emscripten build:

• mujoco_physics.js: ES module loader
• mujoco_physics.wasm: WebAssembly binary
• mujoco_physics.d.ts: TypeScript declarations

Install

npm install @lighttransport/mujoco-wasm

Usage

import loadMujocoPhysics from "@lighttransport/mujoco-wasm";

const mj = await loadMujocoPhysics();
const model = mj.loadModelFromArrayBuffer(mjbArrayBuffer);
if (!model) {
  throw new Error("failed to load model");
}

const data = new mj.PhysicsData(model);
mj.mj_step(model, data);

data.delete();
model.delete();

The loader resolves mujoco_physics.wasm relative to the JavaScript module by default. If your bundler serves WebAssembly assets from another location, pass a custom locateFile option:

const mj = await loadMujocoPhysics({
  locateFile: (path) => `/assets/${path}`,
});

The physics-only build loads precompiled MuJoCo binary models (.mjb) via loadModelFromArrayBuffer. It does not include the browser filesystem path used by the full MuJoCo WASM package.