CODEWITHSUNDEEP
javascriptjqueryloopseachjquery-deferred
Joey Hipolito
Joey Hipolito

Reputation: 3166

Continue loop after a function has finished executing. How to use jquery deffered

I have the following data

var data = [{user:"somename"}, {user:"anothername"}];

I have this function that processes that that, let say checking user if it exist

function process(user) {
    $.ajax({
        url: 'http://domain.com/api',
        success: function(result) {
            if(result == 'success')
                anotherFunction();
            else 
                console.log('error');
        }
    })
}

function anotherFunction() {
     $.ajax({

        // do stuffs
     })
}

$.each(data, function(k,v){ process(v.user); })

The $.each will try to loop even the process and the anotherFunction hasn't finished yet

Question, what can I do to assure that all functions are finished executing before moving on to another index?

I heard I can use jquery deferred.

Upvotes: 0

Views: 768

Answers (1)

Alnitak
Alnitak

Reputation: 339816

Collect the promises returned by your AJAX function, if necessary post-processing that result with .then so that it calls anotherFunction() which must also return the result of $.ajax.

function process() {
    return $.ajax(...).then(function(result) {
        if (result === 'success') {
             return anotherFunction();
        } else {
             return null;  // this might need to change...
        }
    });
}

function anotherFunction() {
    return $.ajax(...);
}

var promises = [];
$.each(data, function(k, v) {
    promises.push(process(v.data));
}

and then wait for all the promises to be resolved:

$.when.apply($, promises).done(function() {
      // all done here
});

NB: in general it's good practise for an AJAX call to produce a non 2xx return code for errors, rather than an error code within a "successful" HTTP call. This then allows the client side code to use normal AJAX error processing (i.e. .fail callbacks) instead of checking for "errors" within AJAX success processing.

Upvotes: 1

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