JSFiddle - React, Tailwind, and code Playground

JavaScript

var something=999;
var something_cachedValue=something;

function doStuff() {
    if(something==something_cachedValue) {//we want it to match
        setTimeout(doStuff, 50);//wait 50 millisecnds then recheck
        return;
    }
    something_cachedValue=something;
    alert('do stuff');
}

doStuff();

function changeSomething() {
    something = 1;
}

setTimeout(changeSomething, 2000);