Question

I am working with the Sharepoint Client Object Model using javascript and looking to make as much of my code as reusable as possible.

Examples of using the COM usually looks like this with a call and then a success delegate function to output the results.

function loadProfile()
{
    var context = SP.ClientContext.get_current();         
    var web = context.get_web();         
    var userInfoList = web.get_siteUserInfoList();
    camlQuery = new SP.CamlQuery();         
    camlQuery.set_viewXml('');         
    this.listItems = userInfoList.getItems(camlQuery);         
    context.load(listItems);         
    context.executeQueryAsync(Function.createDelegate(this, this.onProfileSuccessMethod), Function.createDelegate(this, this.onFail));     

}
function onProfileSuccessMethod(sender, args) 
{
    var item = listItems.itemAt(0);
    var first_name = item.get_item('FirstName');
    var last_name = item.get_item('LastName');
    alert(first_name + " " + last_name);
}

function onFail(sender, args)
{
  alert('Error: ' + args.get_message() + '\n' + args.get_stackTrace());
}

What I am trying to achieve is being able return the values after instantiating an object but given that it is asynchronous I am not sure how this is possible, would I need to “listen” for the call to complete before values are returned.

Would it be something like this? Or can you not have a delegate function internal to the function it creates it from. Apologies for my limited understanding!

var profile = new loadProfile("testid");
alert(profile.onProfileSuccessMethod());


function loadProfile (id) 
{
    this.user_id = id;
    var context = SP.ClientContext.get_current();         
    var web = context.get_web();         
    var userInfoList = web.get_siteUserInfoList();
    camlQuery = new SP.CamlQuery();         
    camlQuery.set_viewXml('');         
    this.listItems = userInfoList.getItems(camlQuery);         
    context.load(listItems);         
    context.executeQueryAsync(Function.createDelegate(this, this.onProfileSuccessMethod), Function.createDelegate(this, this.onFail));    
   this.onProfileSuccessMethod = function() 
{
    var item = listItems.itemAt(0);
    this.first_name = item.get_item('FirstName');
    this.last_name = item.get_item('LastName');
        return this.first_name


    };
}

Answer 1

If it is asynchronous, it is impossible to return values from it. You need to use a callback pattern.

function secondStep(data){
    console.log(data)
}

var profile = new loadProfile("testid", secondStep);

and

function loadProfile (id, callback) 
    ...
    this.onProfileSuccessMethod = function(){
        callback({});
    }