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

Question

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 1

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/

Answer 2

add the following to the end of the first function

return $.Deferred().resolve();

call both functions like so

functionOne().done(functionTwo);

Answer 3

Along with Yoshi's answer, I have found another very simple (callback type) solution for animations.

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:

functionOne(); // one with animations

animationsTest(functionTwo);

Hope this helps some people out!

Answer 4

This answer uses promises, a JavaScript feature of the ECMAScript 6 standard. If your target platform does not support promises, polyfill it with PromiseJs.

You can get the Deferred object jQuery creates for the animation using .promise() on the animation call. Wrapping these Deferreds into ES6 Promises results in much cleaner code than using timers.

You can also use Deferreds directly, but this is generally discouraged because they do not follow the Promises/A+ specification.

The resulting code would look like this:

var p1 = Promise.resolve($('#Content').animate({ opacity: 0.5 }, { duration: 500, queue: false }).promise());
var p2 = Promise.resolve($('#Content').animate({ marginLeft: "-100px" }, { duration: 2000, queue: false }).promise());
Promise.all([p1, p2]).then(function () {
    return $('#Content').animate({ width: 0 }, { duration: 500, queue: false }).promise();
});

Note that the function in Promise.all() returns the promise. This is where magic happens. If in a then call a promise is returned, the next then call will wait for that promise to be resolved before executing.

jQuery uses an animation queue for each element. So animations on the same element are executed synchronously. In this case you wouldn't have to use promises at all!

I have disabled the jQuery animation queue to demonstrate how it would work with promises.

Promise.all() takes an array of promises and creates a new Promise that finishes after all promises in the array finished.

Promise.race() also takes an array of promises, but finishes as soon as the first Promise finished.

Answer 5

Is this what you mean man: http://jsfiddle.net/LF75a/

You will have one function fire the next function and so on, i.e. add another function call and then add your functionONe at the bottom of it.

Please lemme know if I missed anything, hope it fits the cause :)

or this: Call a function after previous function is complete

Code:

function hulk()
{
  // do some stuff...
}
function simpsons()
{
  // do some stuff...
  hulk();
}
function thor()
{
  // do some stuff...
  simpsons();
}

Answer 6

ECMAScript 6 UPDATE

This uses a new feature of JavaScript called Promises

functionOne().then(functionTwo);

Answer 7

You can do it via callback function.

$('a.button').click(function(){
    if (condition == 'true'){
        function1(someVariable, function() {
          function2(someOtherVariable);
        });
    }
    else {
        doThis(someVariable);
    }
});

function function1(param, callback) { ...do stuff callback(); }

Answer 8

Here is a solution for n-calls (recursive function). https://jsfiddle.net/mathew11/5f3mu0f4/7/

function myFunction(array){
var r = $.Deferred();

if(array.length == 0){
    r.resolve();
    return r;
}

var element = array.shift();
// async task 
timer = setTimeout(function(){
    $("a").text($("a").text()+ " " + element);
    var resolving = function(){
        r.resolve();
    }

    myFunction(array).done(resolving);

 }, 500);

return r;
}

//Starting the function
var myArray = ["Hi", "that's", "just", "a", "test"];
var alerting = function (){window.alert("finished!")};
myFunction(myArray).done(alerting);

Answer 9

You can use the javascript Promise and async/await to implement a synchronized call of the functions.

Suppose you want to execute n number of functions in a synchronized manner that are stored in an array, here is my solution for that.

async function executeActionQueue(funArray) {
  var length = funArray.length;
  for(var i = 0; i < length; i++) {
    await executeFun(funArray[i]);
  }
};

function executeFun(fun) {
  return new Promise((resolve, reject) => {
    
    // Execute required function here
    
    fun()
      .then((data) => {
        // do required with data 
        resolve(true);
      })
      .catch((error) => {
      // handle error
        resolve(true);
      });
  })
};

executeActionQueue(funArray);