JSFiddle - React, Tailwind, and code Playground

JavaScript

//hold collidable objects
var collidableObjects = [];

var scene = new THREE.Scene();

var cubeGeo = new THREE.CubeGeometry( 10 , 10 , 10 );

var materialA = new THREE.MeshBasicMaterial( { color: 0xff0000 } );
var materialB = new THREE.MeshBasicMaterial( { color: 0x00ff00 } );

var cubeA = new THREE.Mesh( cubeGeo , materialA );

collidableObjects.push( cubeA );

scene.add( cubeA );

//Change this variable to a larger number to see the processing time explode
var range = 100;

for( var x = 0 ; x < range ; x += 20 ) {
    for( var z = 0; z < range ; z += 20 ) {
        
        if( x === 0 && z === 0 ) continue;
        
        var cube = new THREE.Mesh( cubeGeo , materialB );
        scene.add( cube );
        cube.position.x = x;
        cube.position.z = z;
        collidableObjects.push( cube );
        
        var cube = cube.clone();
        scene.add( cube );
        cube.position.x = x * -1;
        cube.position.z = z;
        collidableObjects.push( cube );
        
        var cube = cube.clone();
        scene.add( cube );
        cube.position.x = x;
        cube.position.z = z * -1;
        collidableObjects.push( cube );
        
        var cube = cube.clone();
        scene.add( cube );
        cube.position.x = x * -1;
        cube.position.z = z * -1;
        collidableObjects.push( cube );
        
    }
}



var camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 0.1, 1000 );
var renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );

camera.position.y = 200;
camera.lookAt( scene.position );

function render() {
    //requestAnimationFrame(render);
    renderer.render(scene, camera);
    console.log( getObjectsWithinRange( cubeA , 30 ) );
}

function getObjectsWithinRange( source , range ) {
    var startTime = new Date().getTime();
    var inRange = [];
    for( var i = 0; i < collidableObjects.length ; ++i ) {
       ...