Want a javascript function to run every minute, but max 3 times

Question

I have a ajax javascript method that pulls data from a page etc.

I want this process to run on a timed interval, say every minute. But I don't want it to loop forever, so max out at 3 times.

What is the best way to implement this?

Answer 1

Like this:

var runCount = 0;    
function timerMethod() {
    runCount++;
    if(runCount > 3) clearInterval(timerId);

    //...
}

var timerId = setInterval(timerMethod, 60000);    //60,000 milliseconds

Answer 2

A closure-based solution, using setInterval() and clearInterval():

// define a generic repeater
var repeater = function(func, times, interval) {
  var ID = window.setInterval( function(times) {
    return function() {
      if (--times <= 0) window.clearInterval(ID);
      func();
    }
  }(times), interval);
};

// call the repeater with a function as the argument
repeater(function() {
  alert("stuff happens!");
}, 3, 60000);

EDIT: Another way of expressing the same, using setTimeout() instead:

var repeater = function(func, times, interval) {
  window.setTimeout( function(times) {
    return function() {
      if (--times > 0) window.setTimeout(arguments.callee, interval);
      func();
    }
  }(times), interval);
};

repeater(function() {
  alert("stuff happens!");
}, 3, 2000);

Maybe the latter is a bit easier to understand.

In the setTimeout() version you can ensure that the next iteration happens only after the previous one has finished running. You'd simply move the func() line above the setTimeout() line.