return array from function javascript

Question

I need to return my behaviors but its not working

function getBehaviorList() {
    var behaviors = getBehaviors();
    console.log("Making behavior list");
    console.log(behaviors);
    $.each(behaviors, function (index, value) {
        if (value.indexOf("User/.lastUploadedChoregrapheBehavior") < 0) {
            $('#installedBehaviors tr:last').after('<tr><td>' + value.split('/').pop() + '</td><td><a href="#" class="btn btn-default" id="' + value + '"><span class="text-color-green glyphicon glyphicon-play-circle"></span> Start</a></td></tr>');
        }
    });
    $("#installedBehaviors a").click(function () {
        startBehavior(this);
    });
}
function getBehaviors() {
    console.log("Getting behaviors");
    session.service("ALBehaviorManager").done(function (behaviorManager) {
        behaviorManager.getUserBehaviorNames().done(function (behaviors) {
            behaviors;
            console.log(behaviors);
            return behaviors;
        });
    }).fail(function (error) {
        console.log("An error occurred: ", error);
    });
}

this is the error i get in the console

Getting behaviors

Making behavior list

undefined

Uncaught TypeError: Cannot read property 'length' of undefined

["User/.lastUploadedChoregrapheBehavior/test","User/actura-test/test", "User/check-update", "User/follow-me"]

dose anyone got an idea why?

You can't return a value from the middle of a callback inside your function. That is quite likely an asynchronous call (in fact 2 nested async calls by the look of it). — iCollect.it Ltd
– iCollect.it Ltd, Commented Sep 25, 2014 at 10:48

iCollect.it Ltd · Accepted Answer · 2014-09-25 10:51:47Z

1

You can't return a value from the middle of a callback inside your function. That is quite likely an asynchronous call (or two it appears).

You can use deferreds or promises to do this. Here is a simple example using a callback:

function getBehaviorList() {
    getBehaviors(function (behaviors) {
        console.log("Making behavior list");
        console.log(behaviors);
        $.each(behaviors, function (index, value) {
            if (value.indexOf("User/.lastUploadedChoregrapheBehavior") < 0) {
                $('#installedBehaviors tr: last ').after(' < tr > < td > ' + value.split(' / ').pop() + ' < /td><td><a href="#" class="btn btn-default" id="' + value + '"><span class="text-color-green glyphicon glyphicon-play-circle"></span > Start < /a></td > < /tr>');
            }
        });
        $("#installedBehaviors a").click(function () {
            startBehavior(this);
        });
    });
}

function getBehaviors(callback) {
    console.log("Getting behaviors");
    session.service("ALBehaviorManager").done(function (behaviorManager) {
        behaviorManager.getUserBehaviorNames().done(function (behaviors) {
            console.log(behaviors);
            callback(behaviors);
        });
    }).fail(function (error) {
        console.log("An error occurred: ", error);
        callback();  // Possibly callback with [] instead.
    });
}

Using deferreds is probably a better pattern, but takes more work and I would need to know more about the services you are calling.

answered Sep 25, 2014 at 10:51

iCollect.it Ltd

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4 Comments

Mathias Over a year ago

its an service from Aldebaran for the NAO robot community.aldebaran-robotics.com/doc/2-1/dev/js/index.html Using the callback im getting an error Uncaught ReferenceError: callback is not defined --- My bad just forgot the callback.. Thanks

iCollect.it Ltd Over a year ago

did you change the first part to getBehaviors(function (behaviors) { etc?

Mathias Over a year ago

I didnt notice this part function getBehaviors(callback) { but fixing that made it all work, so thanks alot :)

iCollect.it Ltd Over a year ago

Aha.. that was the key to making it all work. It turns all your code into a callback, that gets called when the other function finally completed. Glad it helped :)

Dinkheller · Accepted Answer · 2014-09-25 11:00:32Z

0

You are call in upon getBehaviours() --> getting behaviors

Next you are making an async call (it does not have a direct answer timewise, but later.

You are returning to getBehaviorList without any returned values (undefined), which has no length.

Then later you receive the answer from getUserBehaviorNames and the console.log(behaviors).

You need to call a new function from .done()

function continueBuildBehaviorList(behaviors) {
    $.each(behaviors, function (index, value) {
        if (value.indexOf("User/.lastUploadedChoregrapheBehavior") < 0) {
            $('#installedBehaviors tr:last').after('<tr><td>' + value.split('/').pop() + '</td><td><a href="#" class="btn btn-default" id="' + value + '"><span class="text-color-green glyphicon glyphicon-play-circle"></span> Start</a></td></tr>');
        }
    });
    $("#installedBehaviors a").click(function () {
        startBehavior(this);
    });
}

answered Sep 25, 2014 at 11:00

Dinkheller

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3 Comments

iCollect.it Ltd Over a year ago

This example sounds interesting but is not complete.

Dinkheller Over a year ago

Nope. Some work could be done by the user. I explained the problem and showed a way to go. But it is not meant to be complete. Still works :)

iCollect.it Ltd Over a year ago

Still works if you write the missing parts you mean :)

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