Stop recursive setTimeout function

Question

Im running a recursive setTimeout function and I can run it many times, it has a clearTimeout, with this property I can handle how to stop the function running. But I can't figure out how to stop it in another function.

var a = 0;
var b = 0;
function Listener(x, y) {
    var lValue = y == true ? a : b;
    if (lValue < 100) {
        console.log(lValue);
        if(y == true){
            a+=x; 
        }else{
            b+=x;
        } 
        setTimeout(Listener.bind(this, x, y), 1000);
    } else {
        clearTimeout(Listener);
        if(y == true){
            a=0; 
        }else{
            b=0;
        } 
    }
}

When i tried to run it twice, it works:

My doubt is: How can I stop a particular running instance.

Patrick Roberts · Accepted Answer · 2019-06-21 15:33:26Z

A couple notes:

Given the constant timeout of 1000, you should be using setInterval() instead. It will greatly simplify your function, and allow you to cancel the interval whenever you want.
Using global variables is code smell, create an object instead to hold a reference to the value being incremented. Doing so will also allow your function parameters to be more intuitive.

Here's a solution incorporating these two suggestions:

function range (step, start = 0, stop = 100) {
  const state = {
    value: start,
    interval: setInterval(callback, 1000)
  };
  
  function callback () {
    if (state.value < stop) {
      console.log(state.value);
      state.value += step;
    } else {
      console.log('timer done');
      clearInterval(state.interval);
    }
  }

  callback();

  return state;
}

const timer1 = range(10);
const timer2 = range(20);

setTimeout(() => {
  console.log('stopping timer 1');
  clearInterval(timer1.interval);
}, 2500);

setTimeout(() => {
  console.log('timer 2 value:', timer2.value);
}, 3500);

I wrestled a bear once. · Accepted Answer · 2019-06-21 15:07:09Z

1

You could elevate the timer to a higher scope that is accessible by other functions.

var a = 0;
var b = 0;
var timer = null;

function Listener(x, y) {
  var lValue = y == true ? a : b;
  if (lValue < 100) {
    console.log(lValue);
    if (y == true) {
      a += x;
    } else {
      b += x;
    }
    timer = setTimeout(Listener.bind(this, x, y), 1000);
  } else {
    clearTimeout(timer);
    if (y == true) {
      a = 0;
    } else {
      b = 0;
    }
  }
}

function clearTimer() {
  if (timer !== null) clearTimeout(timer);
}

Listener(3, 3);
// clear the timer after 3 secnods
setTimeout(clearTimer, 3000);

answered Jun 21, 2019 at 15:07

I wrestled a bear once.

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Comments

Rinor Dreshaj · Accepted Answer · 2019-06-21 15:09:01Z

0

create a variable and store the reference of setTimout on that variable, after that you just clearTimout with that variable reference

e.x

GLOBAL VARIABLE:

var k = setTimeout(() => { alert(1)}, 10000)

clearTimeout(k)





 var a = 0;
    var b = 0;
    var recursiveFunctionTimeout = null;

    function Listener(x, y) {
        var lValue = y == true ? a : b;

        if (lValue < 100) {
            console.log(lValue);
            if(y == true){
                a+=x; 
            }else{
                b+=x;
            } 
            recursiveFunctionTimeout = setTimeout(Listener.bind(this, x, y), 10);
        } else {
            clearTimeout(recursiveFunctionTimeout);

            if(y == true){
                a=0; 
            }else{
                b=0;
            } 
        }
    }

LOCAL VARIABLE:

var a = 0;
var b = 0;

function Listener(x, y) {
    var lValue = y == true ? a : b;
    var recursiveFunctionTimeout = null;

    if (lValue < 100) {
        console.log(lValue);
        if(y == true){
            a+=x; 
        }else{
            b+=x;
        } 
        recursiveFunctionTimeout = setTimeout(Listener.bind(this, x, y), 10);
    } else {
        clearTimeout(recursiveFunctionTimeout);

        if(y == true){
            a=0; 
        }else{
            b=0;
        } 
    }
}

edited Jun 21, 2019 at 15:09

answered Jun 21, 2019 at 14:52

Rinor Dreshaj

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2 Comments

Johan Sánchez Over a year ago

How can I pass the parameters with your example??

Rinor Dreshaj Over a year ago

You can do that as a global variable, or as a local variable inside

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