Changing the interval of SetInterval while it's running

Question

I have written a javascript function that uses setInterval to manipulate a string every tenth of a second for a certain number of iterations.

function timer(         


        

Answer 1

I'm a beginner in javascript, and didn't found any help in the previous answers (but many good ideas).
This piece of code below accelerates (acceleration > 1) or decelerates (acceleration <1). I hope it might help some people:

function accelerate(yourfunction, timer, refresh, acceleration) {
    var new_timer = timer / acceleration;
    var refresh_init = refresh;//save this user defined value
    if (refresh < new_timer ){//avoid reseting the interval before it has produced anything.
        refresh = new_timer + 1 ;
    };
    var lastInter = setInterval(yourfunction, new_timer);
    console.log("timer:", new_timer);
    function stopLastInter() {
        clearInterval(lastInter);
        accelerate(yourfunction, new_timer, refresh_init, acceleration);
        console.log("refresh:", refresh);
    };
    setTimeout(stopLastInter, refresh);
}

With :

• timer: the setInterval initial value in ms (increasing or decreasing)
• refresh: the time before a new value of timer is calculated. This is the step lenght
• factor: the gap between the old and the next timer value. This is the step height

Answer 2

I had the same question as the original poster, did this as a solution. Not sure how efficient this is ....

interval = 5000; // initial condition
var run = setInterval(request , interval); // start setInterval as "run"

    function request() { 

        console.log(interval); // firebug or chrome log
        clearInterval(run); // stop the setInterval()

         // dynamically change the run interval
        if(interval>200 ){
          interval = interval*.8;
        }else{
          interval = interval*1.2;
        }

        run = setInterval(request, interval); // start the setInterval()

    }

Answer 3

var counter = 15;
var interval = setTimeout(function(){
    // your interval code here
    window.counter = dynamicValue;
    interval();
}, counter);

Answer 4

Inspired by the internal callback above, i made a function to fire a callback at fractions of minutes. If timeout is set to intervals like 6 000, 15 000, 30 000, 60 000 it will continuously adapt the intervals in sync to the exact transition to the next minute of your system clock.

//Interval timer to trigger on even minute intervals
function setIntervalSynced(callback, intervalMs) {

    //Calculate time to next modulus timer event
    var betterInterval = function () {
        var d = new Date();
        var millis = (d.getMinutes() * 60 + d.getSeconds()) * 1000 + d.getMilliseconds();
        return intervalMs - millis % intervalMs;
    };

    //Internal callback
    var internalCallback = function () {
        return function () {
            setTimeout(internalCallback, betterInterval());
            callback();
        }
    }();

    //Initial call to start internal callback
    setTimeout(internalCallback, betterInterval());
};

Answer 5

Use setTimeout() instead. The callback would then be responsible for firing the next timeout, at which point you can increase or otherwise manipulate the timing.

EDIT

Here's a generic function you can use to apply a "decelerating" timeout for ANY function call.

function setDeceleratingTimeout(callback, factor, times)
{
    var internalCallback = function(tick, counter) {
        return function() {
            if (--tick >= 0) {
                window.setTimeout(internalCallback, ++counter * factor);
                callback();
            }
        }
    }(times, 0);

    window.setTimeout(internalCallback, factor);
};

// console.log() requires firebug    
setDeceleratingTimeout(function(){ console.log('hi'); }, 10, 10);
setDeceleratingTimeout(function(){ console.log('bye'); }, 100, 10);

Answer 6

You could use an anonymous function:

var counter = 10;
var myFunction = function(){
    clearInterval(interval);
    counter *= 10;
    interval = setInterval(myFunction, counter);
}
var interval = setInterval(myFunction, counter);

UPDATE: As suggested by A. Wolff, use setTimeout to avoid the need for clearInterval.

var counter = 10;
var myFunction = function() {
    counter *= 10;
    setTimeout(myFunction, counter);
}
setTimeout(myFunction, counter);