javascript accessing an external variable inside ajax function

Question

javascript accessing an external variable inside ajax function

I have implemented dajaxice to fetch a json attribute that I want to make global. However, I am facing an issue where my global variable is always showing up as "undefined":

var recent_id;
$(function(){
    recent_id = Dajaxice.ticker.get_home_timeline(get_home_timeline_callback);
        alert(recent_id);
    });

function get_home_timeline_callback(data){
    if(data==Dajaxice.EXCEPTION){
        alert('Error! Something went wrong!');
    }else{
          var parsed = JSON.parse(data.home_timeline);
          var parsed_id = {'parsed_id':parsed[0].id_str};
          console.log(parsed_id);
    }
    return parsed_id;    
}

@dajaxice_register
def get_home_timeline(request):
    home_timeline = oauth_req(
    'http://api.twitter.com/1/statuses/home_timeline.json?count=1',
    settings.TWITTER_TOKEN_KEY,
    settings.TWITTER_TOKEN_SECRET
    )
    return simplejson.dumps({'home_timeline': home_timeline })

Am I approaching this in the wrong way to access a variable for use in another ajax function?

javascript ajax django json

Answer 1

Answer №1

Your issue appears to be related to asynchronous processing. To resolve this, make adjustments to your get_home_timeline_callback function as shown below:

function handle_tweet_data(response){
    if(response == Dajaxice.EXCEPTION){
        alert('Error! Something went wrong!');
    }else{
          var parsedData = JSON.parse(response.home_timeline);
          var tweetId = {'parsed_id':parsedData[0].id_str};
          console.log(tweetId);
    }
    
    // Debugging purpose
    alert(tweetId);
    
    // Once the value is retrieved, assign it to a global variable
    recentTweetId = tweetId;    
}

Answer 2

Your issue appears to be related to asynchronous processing. To resolve this, make adjustments to your get_home_timeline_callback function as shown below:

function handle_tweet_data(response){
    if(response == Dajaxice.EXCEPTION){
        alert('Error! Something went wrong!');
    }else{
          var parsedData = JSON.parse(response.home_timeline);
          var tweetId = {'parsed_id':parsedData[0].id_str};
          console.log(tweetId);
    }
    
    // Debugging purpose
    alert(tweetId);
    
    // Once the value is retrieved, assign it to a global variable
    recentTweetId = tweetId;    
}

Answer 3

Answer №2

It appears that there is a variable scope issue at play here. The variable parsed_id is declared within the else statement's { }, so its scope is confined to the else statement. When you try to return parsed_id outside of those brackets, it may result in an undefined value.

If you need further clarification on variable scope, you can read more about it here.

To resolve this issue, modify your function as follows:

function get_home_timeline_callback(data)
{
    var parsed_id = "";
        if(data==Dajaxice.EXCEPTION)
        {
            alert('Error! Something happens!');
        }
        else
        {
              var parsed = JSON.parse(data.home_timeline);
              parsed_id = {'parsed_id':parsed[0].id_str};
              console.log(parsed_id);

        }
        return parsed_id;
}

With this change, the variable parsed_id will have a broader scope and can be accessed anywhere within the function. Hopefully, this solution addresses your problem. If not, I apologize for my assumption that the scope was the issue.

Answer 4

It appears that there is a variable scope issue at play here. The variable parsed_id is declared within the else statement's { }, so its scope is confined to the else statement. When you try to return parsed_id outside of those brackets, it may result in an undefined value.

If you need further clarification on variable scope, you can read more about it here.

To resolve this issue, modify your function as follows:

function get_home_timeline_callback(data)
{
    var parsed_id = "";
        if(data==Dajaxice.EXCEPTION)
        {
            alert('Error! Something happens!');
        }
        else
        {
              var parsed = JSON.parse(data.home_timeline);
              parsed_id = {'parsed_id':parsed[0].id_str};
              console.log(parsed_id);

        }
        return parsed_id;
}

With this change, the variable parsed_id will have a broader scope and can be accessed anywhere within the function. Hopefully, this solution addresses your problem. If not, I apologize for my assumption that the scope was the issue.

javascript accessing an external variable inside ajax function

Answer №1

Answer №2

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