JSFiddle - React, Tailwind, and code Playground

JavaScript

function doLater(callback) {
        // if the timeout is larger than about 800ms it "works as expected"
        setTimeout(callback, 1)
        alert("Now")
    }

    var waiting = 0;
    doLater(function () { alert("End(" + waiting + ")") })
    var end = (+new Date) + 2000
    while ((+new Date) < end) { waiting++ }
    alert("Wait-End(" + waiting + ")")