JSFiddle - React, Tailwind, and code Playground

HTML

<button id="start">Start</button>
<button id="btn1">1</button>
<button id="btn2">2</button>
<span id="output">Output: </span>

JavaScript

var playback = [{
    "time": 1176,
    "elemId": "btn1"
}, {
    "time": 1554,
    "elemId": "btn2"
}]

// Do we assume that the array is in order? If not, we have to re-order it to make sure.

var output = document.getElementById('output');
document.getElementById('btn1').onclick = function () {
    output.innerHTML += '1';
}
document.getElementById('btn2').onclick = function () {
    output.innerHTML += '2';
}

for (i = 0; i < playback.length; i++) {
    play = playback[i];
    setTimeout((function (play) {
        return function () {
            document.getElementById(play.elemId).onclick();
        }
    })(play), play.time)
}