JSFiddle - React, Tailwind, and code Playground

by charlescarver

HTML

<div id="rotate"></div>

CSS

div {
    width:100px;
    height:100px;
    background:red;
    -webkit-transform:rotate(30deg);
}

JavaScript

function calculateAngle(element) {
    var tr = (window.getComputedStyle(element, null)).getPropertyValue("-webkit-transform"),
        values = tr.split('(')[1],
        values = values.split(')')[0],
        values = values.split(','),
        a = values[0],
        b = values[1],
        c = values[2],
        d = values[3],
        radians = Math.atan2(b, a);
    if (radians < 0) {
        radians += (2 * Math.PI);
    }
    return Math.round(radians * (180 / Math.PI));
}

var element = document.getElementById("rotate");
alert(calculateAngle(element));