I'm working on a JavaScript driven site where I will have a lot of stuff that need's to be executed in a certain order. A lot of the stuff involves animations and AJAX-loading. Some pseudo code could look like this:
Each step in this is wrapped in a function - one function loads the JSON data, another generates the HTML-elements, a third initializes the jQuery UI slider and so on. Encapsulating the code in functions makes the code easier to read for me, but above all I want to be able to call the functions in different orders depending on what happens on the page and I want to be sure that one function has finished running before the next one is executed.
If there was just regular functions that didn't involve AJAX or jQuery animations I'd just execute the functions I want to execute, one after the other. The problem is that I need to wait for the animations and data retrieving functions to finish before moving on. To aid me both the animation and AJAX methods in jQuery allow me to send along a callback. But here's where I get lost.
What I want it to do is the following:
The ideal thing would be if I could set up this sequence/chain of events in one single place, for example inside an event handler. If I want to call the functions in a different order or not call all of them I would just set up a different sequence/chain. An example could be:
This means that I'd have to be in control over the callbacks in each step.
I hope you understand what I'm looking for. I want to control the entire execution sequence from a single function. This function would be "the conductor of the orchestra" and all the other functions would be the different instrument sections of the orchestra. This conductor functions need's ears so it can hear when the violinist is finished with her solo and can tell the horns to start playing. Excuse me for the corny allegory, but I hopes it makes it easier to understand what I want to do.
Thanks in advance! /Thomas
I found that what I was trying to achieve was slightly overkill for my purposes. So I decided to go with a different approach. I can send one or more boolean variables as a parameters to a function and use them to decide whether to execute a second function or not. Here's an example:
$("#justOneStep").click(function() {
loadImage(false);
});
$("#twoStepsPlease").click(function() {
loadImage(true);
});
function loadImage(boolDoMore) {
// Do the stuff that loads an image
...
if(boolDoMore) {
nextFunction();
}
}
function nextFunction() {
// Do some more stuff
...
}
Not very fancy but easy to understand and control and sufficient for my needs at the moment.
/Thomas