A basic three.js setup

scripts.js

(function(){
    var camera, scene, renderer;
    var geometry, material, mesh;

    // Set the scene size.
    const WIDTH = window.innerWidth;
    const HEIGHT = window.innerHeight;

    // Set some camera attributes.
    const VIEW_ANGLE = 70; // FOV (field of view)
    const ASPECT = WIDTH / HEIGHT;
    const NEAR = 0.01;
    const FAR = 10;

    // Set up the box geometry attributes
    const BOX_WIDTH = 0.2;
    const BOX_HEIGHT = 0.2;
    const BOX_DEPTH = 0.2;

    init();
    animate();

    function init() {
        // Create an empty scene
        scene = new THREE.Scene();

        // Create a WebGL renderer with Antialiasing and add into DOM to display
        renderer = new THREE.WebGLRenderer( { antialias: true } );
        renderer.setSize( WIDTH, HEIGHT );
        document.body.appendChild( renderer.domElement );

        // Create a basic perspective camera
        camera = new THREE.PerspectiveCamera( VIEW_ANGLE, ASPECT, NEAR, FAR );
        camera.position.z = 1;

    
        // Create a geometry and basic material to apply on mesh
        geometry = new THREE.BoxGeometry( BOX_WIDTH, BOX_HEIGHT, BOX_DEPTH );
        material = new THREE.MeshNormalMaterial();

        // Create a mesh object using geometry & material
        mesh = new THREE.Mesh( geometry, material );
        scene.add( mesh );
    }

    // Render Loop to animate
    function animate() {

        requestAnimationFrame( animate );

        mesh.rotation.x += 0.01;
        mesh.rotation.y += 0.02;

        renderer.render( scene, camera );
    }
})();