Question

I’m working on creating a Users collection with the ability to then grab single users inside. This will be used to match from another system, so my desire is to load the users once, and then be able to fine/match later. However, I’m having a problem accessing the outer users collection from an inner method.

function Users(){

    var allUsers;

    this.getUsers = function () {
        // ajax to that Jasmine behaves    
        $.ajax({
            url: '../app/data/jira_users.json',
            async: false,
            dataType: 'json',
            success: function(data) {
                allUsers = data;
            }
        });
        return allUsers;
    };

    this.SingleUser = function (name) {
        var rate = 0.0;
        var position;

        this.getRate = function () {
            if(position === undefined){
                console.log('>>info: getting user position to then find rate');
                this.getPosition();
            }

            $.ajax({
                url: '../app/data/rates.json',
                async: false,
                dataType: 'json',
                success: function(data) {
                    rate = data[position];
                }
            });
            return rate;
        };

        this.getPosition = function () {
            console.log(allUsers);
            //position = allUsers[name];
            return position;
        };

        //set name prop for use later I guess.
        this.name = name;
    };
}

and the test that’s starting all of this:

it("get single user's position", function(){
    var users = new Users();
    var someone = new users.SingleUser('bgrimes');
    var position = someone.getPosition();
    expect(position).not.toBeUndefined();
    expect(position).toEqual('mgr');
});

The getPosition method is the issue (which might be obvious) as allUsers is always undefined. What I have here is yet another attempt, I’ve tried a few ways. I think the problem is how the Users.getUsers is being called to start with, but I’m also unsure if I’m using the outer and inner vars is correct.

Answer 1

Though the others are correct in that this won’t work as you have it typed out, I see the use case is a jasmine test case. So, there is a way to make your test succeed. And by doing something like the following you remove the need to actually be running any kind of server to do your test.

var dataThatYouWouldExpectFromServer = {
    bgrimes: {
        username: 'bgrimes',
        show: 'chuck',
        position: 'mgr'
    }
};

it("get single user's position", function(){
    var users = new Users();
    spyOn($, 'ajax').andCallFake(function (ajaxOptions) {
        ajaxOptions.success(dataThatYouWouldExpectFromServer);
    });
    users.getUsers();
    var someone = new users.SingleUser('bgrimes');
    var position = someone.getPosition();
    expect(position).not.toBeUndefined();
    expect(position).toEqual('mgr');
});

This will make the ajax call return whatever it is that you want it to return, which also allows you to mock out tests for failures, unexpected data, etc. You can set ‘dataThatYouWouldExpectFromServer’ to anything you want at any time.. which can help with cases where you want to test out a few different results but don’t want a JSON file for each result.

Sorta-edit – this would fix the test case, but probably not the code. My recommendation is that any time you rely on an ajax call return, make sure the method you are calling has a ‘callback’ argument. For example:

var users = new Users();
users.getUsers(function () {
    //continue doing stuff
});

You can nest them, or you can (preferably) create the callbacks and then use them as arguments for eachother.

var users = new Users(), currentUser;

var showUserRate = function () {
    //show his rate
    //this won't require a callback because we know it's loaded.
    var rate = currentUser.getRate(); 
}

var usersLoaded = function () {
    //going to load up the user 'bgrimes'
    currentUser = new users.SingleUser('bgrimes');
    currentUser.getRate(showUserRate);
}

users.getUsers(usersLoaded);