Three.js basics – Can't find variable – GLTFLoader animation

Question

I’ve got very basic knowledge of JS. Following three.js docs Loading 3D models I have succesfully rendered 3D object and centered it:

const loader = new GLTFLoader();

loader.load( 'Duck.gltf', function ( duck ) {
    
    const model = duck.scene
    const box = new THREE.Box3().setFromObject( model );
    const center = new THREE.Vector3();
    box.getCenter( center );
    model.position.sub( center ); // center the model
    scene.add( model );

}, undefined, function ( error ) {

    console.error( error );

} );

I would like to animate it now, begining with simple rotation:

/**
 * Animate
 */

const clock = new THREE.Clock()

const tick = () =>
{

    const elapsedTime = clock.getElapsedTime()

    // Update objects
    model.rotation.y = .5 * elapsedTime

    // Update Orbital Controls
    // controls.update()

    // Render
    renderer.render(scene, camera)

    // Call tick again on the next frame
    window.requestAnimationFrame(tick)
}

tick()

But the problem is console returns:

ReferenceError: Can't find variable: model

Answer 1

You have declared model variable inside the functional scope, try to declare it outside

const loader = new GLTFLoader();
let model, box, center;

loader.load( 'Duck.gltf', function ( duck ) {
    
    model = duck.scene
    box = new THREE.Box3().setFromObject( model );
    center = new THREE.Vector3();
    box.getCenter( center );
    model.position.sub( center ); // center the model
    scene.add( model );

}, undefined, function ( error ) {
    console.error( error );
} );

Hopefully, this will work!

Edited

as @prisoner849 suggested in the comments

const clock = new THREE.Clock()
const tick = () =>
{
    const elapsedTime = clock.getElapsedTime()
    // Update objects
    if (model) {
       model.rotation.y = .5 * elapsedTime
    }
    // Update Orbital Controls
    // controls.update()
    // Render
    renderer.render(scene, camera)
    // Call tick again on the next frame
    window.requestAnimationFrame(tick)
}

tick()