You need to assign the canvas.
See BeginnerExample
(from Collection of examples from discourse.threejs.org)
<div id= "container" class="main"></div>
const container = document.getElementById( 'container' );
// https://threejs.org/docs/index.html#api/en/renderers/WebGLRenderer
const renderer = new THREE.WebGLRenderer( { antialias: true } );
renderer.setSize( window.innerWidth, window.innerHeight );
renderer.setClearColor( 0x0099ff, 1 );
// const container = document.createElement( 'div' );
document.body.appendChild( container );
container.appendChild( renderer.domElement );