JSFiddle - React, Tailwind, and code Playground

CSS

body {
	  margin: 0;
}

JavaScript

import * as THREE from 'https://cdn.jsdelivr.net/npm/three@0.121.1/build/three.module.js';
import { OrbitControls } from 'https://cdn.jsdelivr.net/npm/three@0.121.1/examples/jsm/controls/OrbitControls.js';

var camera, scene, renderer;
var geometry, material, mesh;

init();
animate();

function init() {

    camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 0.01, 10 );
    camera.position.set( 1, 0, 0 );

    scene = new THREE.Scene();

    geometry = new THREE.BoxGeometry( 0.2, 0.2, 0.2 );
    material = new THREE.MeshNormalMaterial();

		geometry.faces = [ geometry.faces[ 0 ], geometry.faces[ 1 ] ];
		geometry.mergeVertices();
		console.log( geometry.vertices.length );

    mesh = new THREE.Mesh( geometry, material );
    scene.add( mesh );

    renderer = new THREE.WebGLRenderer( { antialias: true } );
    renderer.setSize( window.innerWidth, window.innerHeight );
    document.body.appendChild( renderer.domElement );
		
		const controls = new OrbitControls( camera, renderer.domElement );

}

function animate() {

    requestAnimationFrame( animate );
    renderer.render( scene, camera );

}