Count animation from number A to B

Question

I am updating a numeric value inside an element by doing intervalled ajax requests.

To make the whole thing a bit more alive,

Answer 1

You can just code it yourself pretty simply:

function animateValue(id, start, end, duration) {
    if (start === end) return;
    var range = end - start;
    var current = start;
    var increment = end > start? 1 : -1;
    var stepTime = Math.abs(Math.floor(duration / range));
    var obj = document.getElementById(id);
    var timer = setInterval(function() {
        current += increment;
        obj.innerHTML = current;
        if (current == end) {
            clearInterval(timer);
        }
    }, stepTime);
}

animateValue("value", 100, 25, 5000);

#value {
    font-size: 50px;
}

<div id="value">100</div>

---

Here's is a more accurate version that self adjusts in case the timer intervals aren't perfectly accurate (which they sometimes aren't):

function animateValue(id, start, end, duration) {
    // assumes integer values for start and end
    
    var obj = document.getElementById(id);
    var range = end - start;
    // no timer shorter than 50ms (not really visible any way)
    var minTimer = 50;
    // calc step time to show all interediate values
    var stepTime = Math.abs(Math.floor(duration / range));
    
    // never go below minTimer
    stepTime = Math.max(stepTime, minTimer);
    
    // get current time and calculate desired end time
    var startTime = new Date().getTime();
    var endTime = startTime + duration;
    var timer;
  
    function run() {
        var now = new Date().getTime();
        var remaining = Math.max((endTime - now) / duration, 0);
        var value = Math.round(end - (remaining * range));
        obj.innerHTML = value;
        if (value == end) {
            clearInterval(timer);
        }
    }
    
    timer = setInterval(run, stepTime);
    run();
}

animateValue("value", 100, 25, 5000);

#value {
    font-size: 50px;
}

<div id="value">100</div>

Answer 2

I used a mixture of all of these to create a function that updates a BehaviorSubject.

function animateValue(subject, timerRef, startValue, endValue, duration){
  if (timerRef) {  clearInterval(timerRef); }
  const minInterval = 100;
  const valueRange = endValue - startValue;
  const startTime = new Date().getTime();
  const endTime = startTime + (duration * 1000);
  const interval = Math.max((endTime-startTime)/valueRange, minInterval);

  function run() {
    const now = new Date().getTime();
    const rangePercent = Math.min(1-((endTime-now)/(endTime-startTime)),1);
    const value = Math.round(rangePercent * valueRange+startValue);

    subject.next(value);
    if (rangePercent >= 1) {
      clearInterval(timerRef);
    }
  }

  timerRef = setInterval(run, interval);
  run();
}

Answer 3

Current solutions do update more often than needed. Here a frame based approach, which is accurate:

function animateValue(obj, start, end, duration) {
  let startTimestamp = null;
  const step = (timestamp) => {
    if (!startTimestamp) startTimestamp = timestamp;
    const progress = Math.min((timestamp - startTimestamp) / duration, 1);
    obj.innerHTML = Math.floor(progress * (end - start) + start);
    if (progress < 1) {
      window.requestAnimationFrame(step);
    }
  };
  window.requestAnimationFrame(step);
}

const obj = document.getElementById('value');
animateValue(obj, 100, -25, 2000);

div {font-size: 50px;}

<div id="value">100</div>

Answer 4

This works well. However, I needed to use a comma within the number. Below is the updated code which checks for commas. Hope someone finds this useful if they stumble across this post.

function animateValue(id, start, end, duration) {

    // check for commas
    var isComma = /[0-9]+,[0-9]+/.test(end); 
    end = end.replace(/,/g, '');

    // assumes integer values for start and end

    var obj = document.getElementById(id);
    var range = end - start;
    // no timer shorter than 50ms (not really visible any way)
    var minTimer = 50;
    // calc step time to show all interediate values
    var stepTime = Math.abs(Math.floor(duration / range));

    // never go below minTimer
    stepTime = Math.max(stepTime, minTimer);

    // get current time and calculate desired end time
    var startTime = new Date().getTime();
    var endTime = startTime + duration;
    var timer;

    function run() {
        var now = new Date().getTime();
        var remaining = Math.max((endTime - now) / duration, 0);
        var value = Math.round(end - (remaining * range));
        obj.innerHTML = value;
        if (value == end) {
            clearInterval(timer);
        }
        // Preserve commas if input had commas
        if (isComma) {
            while (/(\d+)(\d{3})/.test(value.toString())) {
                value = value.toString().replace(/(\d+)(\d{3})/, '$1'+','+'$2');
            }
        }
    }

    var timer = setInterval(run, stepTime);
    run();
}

animateValue("value", 100, 25, 2000); 

Answer 5

HTML

<!DOCTYPE html>
<html>
<head>
    <title>Count</title>
</head>
<body>
    <div id="value">1000</div>
</body>
</html>

JAVASCRIPT snippet

Here is a simple js function decrementing values from a given start number to an end number (object prototype)..

function getCounter(startCount,endcount,time,html){
objects = {
    //you can alternateif you want yo add till you reach the endcount
    startCount:startCount,
    endCount:endcount,
    timer:time
}
this.function = function(){
    let startTm  = objects.startCount,
        timer = objects.timer,
        endCount = objects.endCount;
        //if you want it to add a number just replace the -1 with +1
        /*and dont forget to change the values in the object prototype given a variable of counter*/
    let increament = startTm  < endCount ? 1:-1;
        timmer  = setInterval(function(){
                startTm  += increament;
                html.innerHTML = startTm ;
                if(startTm  == endCount){
                    clearInterval(timmer);
                }
            },timer);
   }
}
// input your startCount,endCount  the timer.....
let doc = document.getElementById('value');

let counter = new getCounter(1000,1,10,doc);
//calling the function in the object
counter.function();

Check out this demo https://jsfiddle.net/NevilPaul2/LLk0bzvm/

Answer 6

Here is one version where increments grow by some defined multiplier (mul). frameDelay is the time delay for each increment. This looks a bit better if you have values that camn

function cAnimate(id, start, end, frameDelay = 100, mul = 1.2) {
    var obj = document.getElementById(id);
    var increment = 2;
    var current = start;
    var timer = setInterval(function() {
        current += increment;
        increment *= mul;
        if (current >= end) {
            current = end;
            clearInterval(timer);
        }

        obj.innerHTML = Math.floor(current).toLocaleString();

    }, frameDelay);
}

cAnimate("counter", 1, 260000, 50);