function wait with return until $.getJSON is finished

function, javascript, jquery

Solution

Updated answer

`getJSON` returns a promise (a read-only deferred), so you can listen to it. But since you need some post-processing, you'd want to chain a `then` which allows you to alter the resolved value.

// Now using `then`
function getThumbnail(vUrl){
  return $.getJSON("http://api.embed.ly/1/oembed?key=:key&url="+vurl).then(function(data){
    return {
      thumbnail:data.thumbnail_url,
      vurl:vurl
    }
  });
}

//and in your call will listen for the custom deferred's done
getThumbnail('the_vurl_').then(function(returndata){
  //received data!
});

Original answer

You can use a deferred object, and listen for the `done()`.

function getThumbnail(vUrl) {
    //create our deferred object
    var def = $.Deferred();

    //get our JSON and listen for done
    $.getJSON("http://api.embed.ly/1/oembed?key=:key&url="+vurl)
        .done(function(data){

            //resolve the deferred, passing it our custom data
            def.resolve({
                thumbnail:data.thumbnail_url,
                vurl:vurl
            });
        });

    //return the deferred for listening
    return def;
}

//and in your call will listen for the custom deferred's done
getThumbnail('the_vurl_')
    .done(function(returndata){
        //received data!
    });

You could return `$.getJSON`'s deferred to get the raw data. But because of "post-processing" into an object, the custom deferred is needed. You could also pass a callback to `getThumbnail()`:

function getThumbnail(vUrl,callback) {
    $.getJSON("http://api.embed.ly/1/oembed?key=:key&url="+vurl,function(returndata){
        callback(returndata);
    });
}

getThumbnail('the_vurl_',function(returndata){
    //received data!
})

Problem

I am writing a function which has to get the thumbnail information from a given video using the embed.ly API, however currently the function returns a value before it even got the JSON result from the API. I am using the following code: ``` function getThumbnail(vUrl) { var thumbnail = ''; var title = ''; var caption = ''; var content = ''; $.when( $.getJSON("http://api.embed.ly/1/oembed?key=:key&url="+vurl) ).then(function(data){ var thumbnail = data.thumbnail_url; console.log(thumbnail); return { thumbnail:thumbnail, vurl:vurl } }); } ``` However when using the Chrome Javascript console I can see that: - the function is called - undefined is returned - XHR request is finished - variable thumbnail content is shown in console This is obviously the wrong order. Any help is greatly appreciated!

Original source