A little function that performs a CPU performance check, based on a similar piece of code orriginally made by Baptise Briel

checkPerf.js

checkPerf() {
    // performance test based on cpu performance
    // higher score means worse performance
    // based on Baptiste Briel's work: http://awams.bbriel.me/27
    let perf = 0;

    const start = (performance || Date).now();
    let array = [];
    for(let i = 0; i < 20000; i++) {
        array = Math.pow(Math.sin(Math.random()), 2);
    }

    const perfTest = (performance || Date).now() - start;

    if(perfTest < 7) {
        // good
        perf = 1;
    }
    else if(perfTest < 14) {
        // medium
        perf = 2;
    }
    else if(perfTest < 22) {
        // low
        perf = 3;
    }
    else {
        // bad: do not use WebGL
        perf = 4;
    }

    // if reduced-motion is on, ship the lightest version possible
    const reduceMotion = window.matchMedia('(prefers-reduced-motion: reduce');

    if(!reduceMotion || reduceMotion.matches) {
        perf = 6;
    }

    return perf;
}