I am trying to increment from 0 to a number (can be any number from 2000 to 12345600000) within a certain duration (1000 ms, 5000 ms, etc). I have created the following:
http://jsfiddle.net/fmpeyton/c9u2sky8/
var counterElement = $(".lg-number");
var counterTotal = parseInt(counterElement.text()/*.replace(/,/g, "")*/);
var duration = 1000;
var animationInterval = duration/counterTotal;
counterElement.text("0");
var numberIncrementer = setInterval(function(){
var currentCounterNumber = parseInt(counterElement.text()/*.replace(/,/g, "")*/);
if (currentCounterNumber < counterTotal){
currentCounterNumber += Math.ceil(counterTotal/duration);
// convert number back to comma format
// currentCounterNumber = addCommas(currentCounterNumber);
counterElement.text(currentCounterNumber);
} else {
counterElement.text(counterTotal);
clearInterval(numberIncrementer);
}
console.log("run incrementer");
}, animationInterval);
function addCommas(number){
for (var i = number.length - 3; i > 0; i -= 3)
number = number.slice(0, i) + ',' + number.slice(i);
return number;
}
And this somewhat works, but it does not respect the duration. I.e. if you increase the number from 1000 to 1000000000, they both take different amounts of time to reach the destination number.
How can I increment from zero to a number in a specific time frame?
As #Mouser pointed out, the issue is that the animationInterval can't be too small (the actual minimum threshold will vary based on the browser and platform). Instead of varying the interval, vary the increment to the counter:
var counterElement = $(".lg-number");
var counterTotal = parseInt(counterElement.text()/*.replace(/,/g, "")*/);
var duration = 1000;
var animationInterval = 10;
var startTime = Date.now();
counterElement.text("0");
var numberIncrementer = setInterval(function(){
var elapsed = Date.now() - startTime;
var currentCounterNumber = Math.ceil(elapsed / duration * counterTotal);
if (currentCounterNumber < counterTotal){
counterElement.text(currentCounterNumber);
} else {
counterElement.text(counterTotal);
clearInterval(numberIncrementer);
}
console.log("run incrementer");
}, animationInterval);
I played around with your fiddle and found that the delay needs to be higher. At 8ms or 16ms, it is accurate enough to handle a second, but not accurate enough to handle half a second. From experimenting, it seems like a delay of 64ms is small enough to seem like it's incrementing smoothly, but big enough to have an accurate effect.
The difference is that the current number is calculated based on the process rather than directly manipulated.
var counterElement = $(".lg-number");
var counterTotal = parseInt(counterElement.data('total'));
var interval = 0;
var duration = parseInt(counterElement.data('duration'));;
var delay = 64
var numberIncrementer = setInterval(function(){
var currentCounterNumber = 0;
interval += delay;
if (interval <= duration){
var progress = interval / duration;
currentCounterNumber = Math.round(progress * counterTotal);
} else {
currentCounterNumber = counterTotal
clearInterval(numberIncrementer);
}
counterElement.text(currentCounterNumber);
}, delay);
http://jsfiddle.net/c9u2sky8/5/
Also: Javascript timers are not perfectly accurate. But this should be accurate enough for UI use cases.
Related
I am trying to make a counter that counts to big numbers such as 6 billion (like google's random number generator) but the browser freezes.
var counter = document.querySelector("#blahblahblah");
var nb = 0;
var ne = 6_000_000_000;
for (;nb<=ne;nb++) {
counter.innerHTML = nb;
};
The best thing you can do is use requestAnimationFrame. This represents the fastest rate that you can update the DOM.
Use the callback to update your element text to the number proportional to the time allowed; 3 seconds (a few) from your question title
const runCounter = (num, timeout, el) => {
let start;
const step = (ts) => {
if (!start) {
start = ts; // record the first iteration timestamp
}
const progress = (ts - start) / timeout; // how far into the time span
if (progress < 1) {
el.textContent = Math.floor(num * progress);
requestAnimationFrame(step); // request the next frame
} else {
el.textContent = num; // finish
}
};
requestAnimationFrame(step);
};
runCounter(6_000_000_000, 3000, document.getElementById("blahblahblah"));
<output id="blahblahblah">0</output>
It's kind of math problem. I want to fire specific number of setTimeout (the number is based on an array length) in a specific period of time (say, 5 seconds).
The first setTimeout should start at 0 sec. and the last at 5 sec.. All timeouts between should start with an ease-in effect, so that each timeout starts faster.
There's an example which ilustrates what I want to achieve exactly.
I'm struggling around this line:
next += timePeriod/3.52/(i+1);
which works almost perfect in demo example (for any timePeriod), but obviously it doesn't work for a different letters.length as I have used static number 3.52.
How do I calculate next?
var letters = [
'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T'
];
var div = $('#container');
var timePeriod = 5000; // 5 seconds;
var perLetter = timePeriod/(letters.length-1); // it gives equal time between letters
var next = 0;
for(var i=0; i<letters.length; i++){
setTimeout(function(letter){
//div.append('<span class="letter">' + letter + '</span>');
// Used "|" instead of letter, For better redability:
div.append('<span class="letter">|</span>');
}, next, letters[i]);
// Can't find the logic here:
next += timePeriod/3.52/(i+1);
};
///////////////// FOR DEMO: ///////////////
var sec = timePeriod/1000;
var secondsInterval = setInterval(seconds, 1000);
var demoInterval = setInterval(function(){
sec >= 0 || clearInterval(demoInterval);
div.append('\'');
}, 30);
function seconds(){
sec || clearInterval(secondsInterval);
$('#sec').text(sec-- || 'DONE');
}
seconds();
.letter{
color : red;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<span id=container></span>
<span id=sec class=letter></span>
var steps = letters.length;
var target = timePeriod;
function easeOutQuad(t, b, c, d) {
t /= d;
return -c * t*(t-2) + b;
};
var arrayOfTimeouts = new Array(steps);
var n;
var prev = 0;
for(var i = 1; i <= steps; i++){
n = easeOutQuad(i, 0.0, target, steps);
arrayOfTimeouts[i-1] = n-prev;
prev = n;
}
This one should work with any input value.
fiddle
Note that the graph appears to be slightly too fast but I believe that discrepancy to be a product of timing imperfections, as the sum of my array equals the timePeriod exactly.
more on easing equations
Here's a solution based on a geometric series. It's a bit goofy but it works. It generates an array with your timeout values.
Steps = size of your array.
Target = the total time.
var steps = 50;
var target = 5000;
var fraction = 1.5 + steps / 7;
var ratio = (fraction-1) / fraction;
var n = target / fraction;
var sum = 0;
var arrayOfTimeouts = new Array(steps);
for(var i = 0; i < steps; i++){
sum += n;
arrayOfTimeouts[i] = n;
n *= ratio;
}
console.log(arrayOfTimeouts, sum);
I'm attempting to generate a set of values every millisecond.
By using window.performance.now(), I've determined that 1000 points (1 second worth of data) requires approximately 1 millisecond worth of processing time.
So... why is a log statement generated every 3-ish seconds rather than every 1 second when my condition for generating the statement is that I have generated 1000 points?
The code is included below. And here is a link to jsfiddle: http://jsfiddle.net/MWadX/421/
var c = 0;
var m = 0;
var t = 0;
var x = 0;
var y = 0;
window.setInterval(function()
{
var e;
var s;
if (c === 0)
{
m = Date.now();
}
s = window.performance.now();
x += Math.random();
y += Math.random();
c++;
e = window.performance.now();
t += e - s;
if (c !== 1000)
{
return;
}
console.log(t.toFixed(0).toString() + " milliseconds");
console.log((Date.now() - m).toFixed(0).toString() + " milliseconds");
c = 0;
m = 0;
t = 0;
x = 0;
y = 0;
}, 1);
setInterval, setTimeout, and Minimum Timeouts
According to the Mozilla Development Network setInterval and setTimeout have a minimum timeout. This value varies somewhat between browsers, but the HTML5 spec specifies a minimum timeout of 4ms, and this value is pretty well respected in browsers made after 2010. If you pass a lower timeout, it will be internally inflated to the minimum.
Inactive Tabs
In background tabs, the timeout is restricted even further to a minimum of 1000ms.
I have this counter JavaScript snippet:
var START_DATE = new Date("October 24, 2015 11:00:00"); // start
var INTERVAL = 1; // sec
var START_VALUE = 0; // init value
var INCREMENT = 0.13; // value per sec
var count = 0;
window.onload = function()
{
var msInterval = INTERVAL * 1000;
var now = new Date();
count = parseInt((now - START_DATE)/msInterval,10) * INCREMENT + START_VALUE;
document.getElementById('count').innerHTML = count.toFixed(2);
setInterval("count += INCREMENT; document.getElementById('count').innerHTML = count.toFixed(2);", msInterval);
}
The counter may eventually display values in thousands and millions. My question is how to separate the thousands with a comma/blank space? I tried to achieve this via CSS, but apparently the options available here are not very practical. I was wondering on a possible solution in JavaScript. I found this on jsfiddle, but I am not sure how to apply it on the result of the counter?
function addCommas(n){
var rx= /(\d+)(\d{3})/;
return String(n).replace(/^\d+/, function(w){
while(rx.test(w)){
w= w.replace(rx, '$1,$2');
}
return w;
});
}
You can use javascript's built in toLocaleString function. Here is an example from MDN
var number = 3500;
console.log(number.toLocaleString()); // Displays "3,500" if in U.S. English locale
There are some additional options you can use with that function, but they are not all supported by various browsers. Basic use should work though.
I have a really simple JS counter which I display on a dashboard like screen which does the following:
Every 5 minutes it makes an jsonp call and retrieves a "total" number
It then displays this number to the screen by incrementing the last total displayed till it is equal to the new total. (the number can only ever increase)
I'm having some trouble with making the number increment smoothly. What I would like to do is find a delta (i.e. New total - old total) and increment the number gradually over the 5 minutes till the next call so it looks like a nice smooth transition.
Any ideas on how I can do this?
Currently some of my code looks like this (This block get's called every 5mins. And yes, it's in dire need of a refactor...)
var LAST_NUMBER_OF_SESSIONS = null;
var five_minutes_in_seconds = 300;
var new_number_of_sessions;
$.getJSON('http://blah.com/live_stats/default_jsonp.aspx?callback=?', function(data) {
if(LAST_NUMBER_OF_SESSIONS === null){
LAST_NUMBER_OF_SESSIONS = data.total_sessions;
}
new_number_of_sessions = data.total_sessions;
var delta = Math.floor(new_number_of_sessions - LAST_NUMBER_OF_SESSIONS);
var time_interval = (five_minutes_in_seconds / delta) * 1000;
var old_value = LAST_NUMBER_OF_SESSIONS;
var new_value = null;
sessions_interval = setInterval(function (){
new_value = parseInt(old_value, 10) + 1;
$('#stats').text(new_value);
old_value = new_value;
if(new_value >= new_number_of_sessions){
clearInterval(sessions_interval);
}
}, time_interval);
LAST_NUMBER_OF_SESSIONS = new_value;
});
}
This code it seems to increment the number very quickly at the start of the 5min period and then stop so it's not exactly right...
Try this:
var total = 0,
delta = 0,
stats = $('#stats').text( total );
function increment() {
var v = +stats.text();
if ( v < total ) {
stats.text( v + 1 );
} else {
$.getJSON('http://...', function(data) { // added data here
delta = Math.floor( 300000 / ( data.total_sessions - total ) );
total = data.total_sessions;
});
}
setTimeout(increment, delta);
}
Update:
In order to test my code, I had to simulate the JSON reponse - I used an array of numbers. See here: http://jsfiddle.net/simevidas/MwQKM/
(In the demo, I use an interval of 5 seconds instead of 5 minutes.)
I am not exactly sure why your code doesn't work as expected, although I suspect that it has to do with line LAST_NUMBER_OF_SESSIONS = new_value;. I wrote something similar and it works fine. It's not that different from what you have, minus that last line of code.