Wait till a Function with animations is finished until running another Function

Mark Pieszak - Trilon.io picture Mark Pieszak - Trilon.io · Aug 24, 2012 · Viewed 197.6k times · Source

I'm having an issue with normal (non-ajax) functions that involve lots of animations within each of them. Currently I simply have a setTimeout between functions, but this isn't perfect since no browsers / computers are the same.

Additional Note: They both have separate animations/etc that collide.

I can't simply put one in the callback function of another

// multiple dom animations / etc
FunctionOne();

// What I -was- doing to wait till running the next function filled
// with animations, etc

setTimeout(function () { 
    FunctionTwo(); // other dom animations (some triggering on previous ones)
}, 1000); 

Is there anyway in js/jQuery to have:

// Pseudo-code
-do FunctionOne()
-when finished :: run -> FunctionTwo()

I know about $.when() & $.done(), but those are for AJAX...


  • MY UPDATED SOLUTION

jQuery has an exposed variable (that for some reason isn't listed anywhere in the jQuery docs) called $.timers, which holds the array of animations currently taking place.

function animationsTest (callback) {
    // Test if ANY/ALL page animations are currently active

    var testAnimationInterval = setInterval(function () {
        if (! $.timers.length) { // any page animations finished
            clearInterval(testAnimationInterval);
            callback();
        }
    }, 25);
};

Basic useage:

// run some function with animations etc    
functionWithAnimations();

animationsTest(function () { // <-- this will run once all the above animations are finished

    // your callback (things to do after all animations are done)
    runNextAnimations();

});

Answer

Yoshi picture Yoshi · Aug 27, 2012

You can use jQuery's $.Deferred

var FunctionOne = function () {
  // create a deferred object
  var r = $.Deferred();

  // do whatever you want (e.g. ajax/animations other asyc tasks)

  setTimeout(function () {
    // and call `resolve` on the deferred object, once you're done
    r.resolve();
  }, 2500);

  // return the deferred object
  return r;
};

// define FunctionTwo as needed
var FunctionTwo = function () {
  console.log('FunctionTwo');
};

// call FunctionOne and use the `done` method
// with `FunctionTwo` as it's parameter
FunctionOne().done(FunctionTwo);

you could also pack multiple deferreds together:

var FunctionOne = function () {
  var
    a = $.Deferred(),
    b = $.Deferred();

  // some fake asyc task
  setTimeout(function () {
    console.log('a done');
    a.resolve();
  }, Math.random() * 4000);

  // some other fake asyc task
  setTimeout(function () {
    console.log('b done');
    b.resolve();
  }, Math.random() * 4000);

  return $.Deferred(function (def) {
    $.when(a, b).done(function () {
      def.resolve();
    });
  });
};

http://jsfiddle.net/p22dK/