Databases
StackOverflow2013
Postsdbo
POHow can jQuery deferred be used?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POHow can jQuery deferred be used?
    primarykey
    data
    text
    <p>jQuery 1.5 brings the new Deferred object and the attached methods <a href="http://api.jquery.com/jQuery.when/" rel="noreferrer"><code>.when</code></a>, <a href="http://api.jquery.com/category/deferred-object/" rel="noreferrer"><code>.Deferred</code></a> and <a href="https://github.com/jquery/jquery/blob/1.5/src/core.js#L808" rel="noreferrer"><code>._Deferred</code></a>.</p> <p>For those who havn't used <code>.Deferred</code> before I've annotated the source for <a href="http://jsfiddle.net/Raynos/Hufjr/" rel="noreferrer">it</a></p> <p>What are the possible usages of these new methods, how do we go about fitting them into patterns?</p> <p>I have already read the <a href="http://api.jquery.com/category/deferred-object/" rel="noreferrer">API</a> and the <a href="https://github.com/jquery/jquery/blob/1.5/src/core.js#L892" rel="noreferrer">source</a>, so I know what it does. My question is how can we use these new features in everyday code?</p> <p>I have a simple <a href="http://jsfiddle.net/Raynos/Vg5sY/9/" rel="noreferrer">example</a> of a buffer class that calls AJAX request in order. (Next one start after previous one finishes).</p> <pre><code>/* Class: Buffer * methods: append * * Constructor: takes a function which will be the task handler to be called * * .append appends a task to the buffer. Buffer will only call a task when the * previous task has finished */ var Buffer = function(handler) { var tasks = []; // empty resolved deferred object var deferred = $.when(); // handle the next object function handleNextTask() { // if the current deferred task has resolved and there are more tasks if (deferred.isResolved() &amp;&amp; tasks.length &gt; 0) { // grab a task var task = tasks.shift(); // set the deferred to be deferred returned from the handler deferred = handler(task); // if its not a deferred object then set it to be an empty deferred object if (!(deferred &amp;&amp; deferred.promise)) { deferred = $.when(); } // if we have tasks left then handle the next one when the current one // is done. if (tasks.length &gt; 0) { deferred.done(handleNextTask); } } } // appends a task. this.append = function(task) { // add to the array tasks.push(task); // handle the next task handleNextTask(); }; }; </code></pre> <p>I'm looking for demonstrations and possible uses of <code>.Deferred</code> and <code>.when</code>.</p> <p>It would also be lovely to see examples of <code>._Deferred</code>. </p> <p>Linking to the new <a href="https://github.com/jquery/jquery/blob/1.5/src/ajax.js" rel="noreferrer"><code>jQuery.ajax</code></a> source for examples is cheating.</p> <p><strong>Bounty:</strong> Show us what techniques are available when we abstract away whether an operation is synchronously or asynchronously done.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USUfuk Hacıoğulları
    1. USRaynos
    plurals
    1. PL
      singulars
      1. LTLinked
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTDuplicate
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POHow can jQuery deferred be used?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POHow can jQuery deferred be used?
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POHow can jQuery deferred be used?
      1. This table or related slice is empty.
      1. VTUpMod
    1. COFrom the FAQ: **avoid** asking subjective questions where...every answer is equally valid: “What’s your favorite ______?” (their emphasis)
      singulars
      1. POHow can jQuery deferred be used?
      1. UST.J. Crowder
    2. CO@T.J.Crowser I'll look at rewording it.
      singulars
      1. POHow can jQuery deferred be used?
      1. USRaynos
    3. COIt's a good question but there can't be **that** many people who can answer :-)
      singulars
      1. POHow can jQuery deferred be used?
      1. USPointy
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload