Three.js - Responsive

HTML

<canvas id="c"></canvas>
  
<script src="https://threejsfundamentals.org/threejs/resources/threejs/r94/three.min.js"></script>

CSS

body {
        margin: 0;
    }
    #c {
        width: 100vw;
        height: 100vh;
        display: block;
    }

JavaScript

// Three.js - Responsive
// from https://threejsfundamentals.org/threejs/threejs-responsive.html

  'use strict';

function main() {
  const canvas = document.querySelector('#c');
  const renderer = new THREE.WebGLRenderer({canvas: canvas});

  const fov = 75;
  const aspect = 2;  // the canvas default
  const zNear = 0.1;
  const zFar = 5;
  const camera = new THREE.PerspectiveCamera(fov, aspect, zNear, zFar);
  camera.position.z = 1.2;

  const scene = new THREE.Scene();

  {
    const color = 0xFFFFFF;
    const intensity = 1;
    const light = new THREE.DirectionalLight(color, intensity);
    light.position.set(-0.5, 0.5, 2);
    scene.add(light);
  }

  const boxWidth = 1;
  const boxHeight = 1;
  const boxDepth = 1;
  const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);

  const material = new THREE.MeshStandardMaterial({color: 'hsl(160,50%,50%)', metalness: 0, roughness: 1});
  const cube = new THREE.Mesh(geometry, material);
  scene.add(cube);

  function resizeRendererToDisplaySize(renderer) {
    const canvas = renderer.domElement;
    const width = canvas.clientWidth;
    const height = canvas.clientHeight;
    const needResize = canvas.width !== width || canvas.height !== height;
    if (needResize) {
      renderer.setSize(width, height, false);
    }
    return needResize;
  }

  function render(time) {
    time *= 0.001;

    if (resizeRendererToDisplaySize(renderer)) {
      const canvas = renderer.domElement;
      camera.aspect = canvas.clientWidth / canvas.clientHeight;
      camera.updateProjectionMatrix();
    }


    renderer.render(scene, camera);

    requestAnimationFrame(render);
  }

  requestAnimationFrame(render);
}

main();