Add JavaScript bindings and WASM support

Co-authored-by: Matija Kecman <matijak@google.com>
Co-authored-by: Sebastian Noreña Rendón <sebas.norena@creativa77.com.ar>
Co-authored-by: Kyle Bayes <kylebayes@google.com>
PiperOrigin-RevId: 826479070
Change-Id: I25acf36e6c20b091d8492e10798d028ae66f6733

wasm/tests/sandbox/index.html

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+<!--
+ Copyright 2025 DeepMind Technologies Limited
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8" />
+    <title>MuJoCo WebAssembly</title>
+  </head>
+  <body>
+    <script type="module" src="./main.ts"></script>
+  </body>
+</html>

wasm/tests/sandbox/main.ts

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+// Copyright 2025 DeepMind Technologies Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { MainModule, MjData, MjModel } from "../../dist/mujoco_wasm"
+import loadMujoco from "../../dist/mujoco_wasm.js"
+
+declare function loadMujoco(): Promise<MainModule>;
+
+async function main() {
+  const mujoco: MainModule = await loadMujoco();
+
+  (mujoco as any).FS.mkdir('/working');
+  (mujoco as any).FS.mount((mujoco as any).MEMFS, {root: '.'}, '/working');
+
+  const xmlContent = `
+    <mujoco model="Box falling">
+      <option viscosity="1"/>
+      <worldbody>
+        <light diffuse=".5 .5 .5" pos="0 0 3" dir="0 0 -1"/>
+        <geom name="MyFloor" type="plane" size="1 1 0.1" rgba=".9 0 0 1" user="5 4 3 2 1"/>
+        <geom name="MyWall" type="plane" size="0.1 1 0.1" rgba="0 1 0 1" user="5 4 3"/>
+        <body pos="0 0 1" name="MyBox">
+          <joint type="free"/>
+          <geom name="MyBoxGeom" type="box" size=".1 .2 .3" rgba="0 .9 0 1"/>
+        </body>
+      </worldbody>
+    </mujoco>`;
+
+  (mujoco as any).FS.writeFile('/working/hello.xml', xmlContent);
+  let model: MjModel|undefined;
+  let data: MjData|undefined;
+
+  try {
+    console.log('Hello world!: Loading model');
+    model = mujoco.MjModel.loadFromXML('/working/hello.xml');
+    if (!model) {
+      throw new Error('Failed to load model');
+    }
+    data = new mujoco.MjData(model);
+    if (!data) {
+      throw new Error('Failed to load data');
+    }
+
+    // Add your test code here...
+
+  } finally {
+    model?.delete();
+    data?.delete();
+    (mujoco as any).FS.unmount('/working');
+  }
+}
+
+main()

wasm/tests/sandbox/vite.sandbox.config.ts

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+// Copyright 2025 DeepMind Technologies Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { defineConfig } from "vite"
+
+export default defineConfig({
+  root: 'tests/sandbox',
+  base: './',
+  build: {
+    outDir: '../../sandbox-dist',
+    emptyOutDir: true,
+  },
+  server: {
+    open: true,
+  },
+})