JSFiddle - React, Tailwind, and code Playground

JavaScript

function testCallBack() {
    one(two);
}

function one(callback) {
    setTimeout(function () {
        alert("delay 1");
        callback();
    }, 2000);
}

function two() {
    setTimeout(function () {
        alert("delay 2")
    }, 1000);
}

testCallBack();