Little script to animate numeric values

animateCount.js

/**
 * animateCount
 *
 * Usage:
 *   animateCount({
 *     selector: '.your-selector',  // the selector for the element to animate
 *     from: 0,                     // the value to animate from
 *     to: 50,                      // the value to animate to 
 *     duration: 1000               // animation duration in miliseconds, defaults to 1000
 *   })
 */

export const animateCount = ({
    selector = null,
    from = 0,
    to = 0,
    duration = 1000,
    pad = false,
    onEnd = null
}) => {
    const obj = document.querySelector(selector);
    const range = to - from;
    let current = from;
    let increment = to > from? 1 : -1;
    let stepTime = Math.abs(Math.floor(duration / range));
    
    function zeroPad(num, places) {
        if(!!pad) {
            const zero = places - num.toString().length + 1;
            return Array(+(zero > 0 && zero)).join("0") + num;
        }
    }
    
    const timer = setInterval(() => {
        current += increment;
        obj.innerHTML = zeroPad(current, 2);
        
        if (current == to) {
            clearInterval(timer);
            if(typeof onEnd === 'function') {
                onEnd.apply(this, arguments);
            }
        }
    }, stepTime);
}