CODEWITHSUNDEEP
javascriptjquerypromise
Philip Kirkbride
Philip Kirkbride

Reputation: 22859

How to use jQuery .When .done

I'm trying to run one function after another function completes.

 $.when(saveCanvas(canvas)).done(setWallPaper());

Each function works fine on it's own but when I run the code above it only runs the first function.

What do I need to change?

Upvotes: 7

Views: 32917

Answers (3)

Philip Kirkbride
Philip Kirkbride

Reputation: 22859

Looking back at this now, this seems to be how it works with jQuery:

function f1() {
	alert("function one");
}

$.when( f1() ).done(function() {
  alert("function 1 is done running function two");
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Note: This is identical to my method I posted in the question so essentially it should have worked. Though jQuery may have changed over the last 3 years. Most likely was a problem with functions being called.

Upvotes: 3

Crash Override
Crash Override

Reputation: 461

another wild guess:

$.when(saveCanvas(canvas)).done(function(){
    setWallPaper()
});

Upvotes: 2

James Glass
James Glass

Reputation: 4300

According to a comment on another SO question, $.when expects deferred objects as arguments. If you don't pass anything, the callbacks will be invoked immediately.

Does setWallPaper() appear to not be working because it is actually being run before saveCancas(canvas)? saveCanvas() is not actually a deferred object, which when expects it to be. To make it a deferred object, add dfr = $.Deferred(); to the beginning of your saveCanvas() function and return dfr.promise(); to the end of it. Check out this SO answer for more details.

function saveCanvas(canvas)
{
    dfr = $.Deferred();
    //Your code
    return dfr.promise();
}

Read more: http://api.jquery.com/jQuery.when/

Upvotes: 9

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