JAVASCRIPT

Renderer in three js

//rendering all of the scene components into the canvas element. 
// define the renderer
  renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true });
  renderer.setPixelRatio(window.devicePixelRatio);
  renderer.setSize(window.innerWidth, window.innerHeight);

  // append the rendered to the dom
  document.body.appendChild(renderer.domElement);

  // render the scene
  renderer.render(scene, camera);

Three Js Render

import './style.css'
import * as THREE from 'three'

// Scene
const scene = new THREE.Scene()

// Object
const geometry = new THREE.BoxGeometry(1, 1, 1)
const material = new THREE.MeshBasicMaterial({ color: 0xff0000 })
const mesh = new THREE.Mesh(geometry, material)
scene.add(mesh)

// Sizes
const sizes = {
    width: 800,
    height: 600
}

// Camera
const camera = new THREE.PerspectiveCamera(75, sizes.width / sizes.height)
camera.position.z = 3
scene.add(camera)

// Renderer
const renderer = new THREE.WebGLRenderer({
    canvas: document.querySelector('canvas.webgl')
})
renderer.setSize(sizes.width, sizes.height)
renderer.render(scene, camera)

what is renderer in three.js

import * as THREE from 'three'
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls'

const scene = new THREE.Scene()

const camera = new THREE.PerspectiveCamera(
    75,
    window.innerWidth / window.innerHeight,
    0.1,
    1000
)
camera.position.z = 2

const renderer = new THREE.WebGLRenderer()
renderer.setSize(window.innerWidth, window.innerHeight)
document.body.appendChild(renderer.domElement)

new OrbitControls(camera, renderer.domElement)

const geometry = new THREE.BoxGeometry()
const material = new THREE.MeshBasicMaterial({
    color: 0x00ff00,
    wireframe: true,
})

const cube = new THREE.Mesh(geometry, material)
scene.add(cube)

window.addEventListener('resize', onWindowResize, false)
function onWindowResize() {
    camera.aspect = window.innerWidth / window.innerHeight
    camera.updateProjectionMatrix()
    renderer.setSize(window.innerWidth, window.innerHeight)
    render()
}

function animate() {
    requestAnimationFrame(animate)

    cube.rotation.x += 0.01
    cube.rotation.y += 0.01

    render()
}

function render() {
    renderer.render(scene, camera)
}

animate()