Ajax – Return Results of Ajax Request in Coffeescript

ajaxcoffeescript

Still getting my head around CoffeeScript and and seeing what its capable of.

I've written a method that makes a ajax call and I'm wanting to return the results.

For example:

GetViewedItem: (foo) ->
    $.ajax '/Foo/Bar/',
    type: 'GET',
    data: { id: $(foo).data('fooId') }
    success: (data) ->
        data

and I want to return data. Is there a clever way of doing this in CoffeeScript or do I just have to declare a variable?

Thanks

Best Answer

You can't really return the data on an AJAX request that way since it is asynchronous. Meaning, by the time the success callback is called, your GetViewedItem method will have finished executing.

Normally, you would continue doing whatever you need to do with the AJAX data in the success callback or call a method from the success callback that deals with the data accordingly.

handleViewedItem: (data) ->
    // Do something now that the AJAX call is complete.

GetViewedItem: (foo) ->
    $.ajax '/Foo/Bar/',
        type: 'GET',
        data: { id: $(foo).data('fooId') }
        success: (data) ->
            handleViewedItem data

This is probably one of the most important concepts to understand when using JS and AJAX.

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Here's what your code would look like if changed as suggested:

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I read this question and implemented the approach that has been stated regarding setting the response HTTP status code to 278 in order to avoid the browser transparently handling the redirects. Even though this worked, I was a little dissatisfied as it is a bit of a hack.

After more digging around, I ditched this approach and used JSON. In this case, all responses to AJAX requests have the status code 200 and the body of the response contains a JSON object that is constructed on the server. The JavaScript on the client can then use the JSON object to decide what it needs to do.

I had a similar problem to yours. I perform an AJAX request that has 2 possible responses: one that redirects the browser to a new page and one that replaces an existing HTML form on the current page with a new one. The jQuery code to do this looks something like:

$.ajax({
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    url: reqUrl,
    data: reqBody,
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            // data.redirect contains the string URL to redirect to
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});

The JSON object "data" is constructed on the server to have 2 members: data.redirect and data.form. I found this approach to be much better.

Best Answer

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