CODEWITHSUNDEEP
javascript
user3328513
user3328513

Reputation: 199

javascript variables in method use outside the method

Here is my code:

var count = 0;

function retrieveCurrentListProperties() {
    clientContext = new SP.ClientContext.get_current();
    web = clientContext.get_web();
    var list = web.get_lists().getByTitle("Urgent Alerts");
    var camlQuery = new SP.CamlQuery();
    var q =  "<View><Query><Where><Eq><FieldRef Name='End_x0020_Date'/><Value Type='DateTime'><Today/></Value></Eq></Where></Query></View>";
    camlQuery.set_viewXml(q);
    this.listItems = list.getItems(camlQuery);
    clientContext.load(this.listItems);
    clientContext.executeQueryAsync(Function.createDelegate(this, this.onCListItemsLoadSuccess), 
    Function.createDelegate(this, this.onQueryFailed));

}

function onCListItemsLoadSuccess(sender, args) {

    var count1 = 0;
    var listEnumerator = this.listItems.getEnumerator();
    //iterate though all of the items

count1 = this.listItems.get_count();


}




function onQueryFailed(sender, args) {
    alert('request failed ' + args.get_message() + '\n' + args.get_stackTrace());
}



                count = 1;

This code retrieves a list from sharepoint and then counts how many items are in that list. I need count1 to be used in another part where count=1 but obviously if I did count=count1 it would throw an error. How can I used count1 in the way that I want

Upvotes: 0

Views: 608

Answers (1)

Vadim Gremyachev
Vadim Gremyachev

Reputation: 59338

Since SP.ClientContext.executeQueryAsync method executes the current pending request asynchronously on the server, two approaches are commonly used to control the sequential execution of asynchronous calls in SharePoint.

  • Callbacks
  • Deferred

With callback approach you declare your function like this

function getData(Success,Error) {
   //...
   clientContext.executeQueryAsync(function() {
             var result = ...
             Success(result);
           },
           Error
    );
}

Deferred approach is based on a Promises pattern, please refer this article for a details about the usage of Promises with CSOM.

Example with callback approach

function getItemsCount(listTitle,Success,Error) {
    var clientContext = new SP.ClientContext.get_current();
    var web = clientContext.get_web();
    var list = web.get_lists().getByTitle(listTitle);
    var qry = SP.CamlQuery.createAllItemsQuery();
    var listItems = list.getItems(qry);
    clientContext.load(listItems);
    clientContext.executeQueryAsync(function() {
         var count = listItems.get_count();
         Success(count);
       },
       Error
    );
}


//Usage
getItemsCount('Tasks', function(tasksCount){
    //...
    console.log('Tasks count:' + tasksCount);
   },
   function(sender, args) {
    console.log('Error:' + args.get_message());
   }
);

Recommendations

Avoid global variables

Wrap your code in a scoping function and use variables local to that scoping function, and make your other functions closures within it

(function() { // Begin scoping function
    var clientContext; // Global to your code, invisible outside the scoping function
    function loadListItems(listTitle) {
        // ...
    }
})();

Usage of Function.createDelegate

In most cases, there is no need to wrap handlers using Function.createDelegate, instead you could write:

ctx.executeQueryAsync(succeeded,failed);

or

ctx.executeQueryAsync(function(){
    //...
  },
  function(sender,args){
    //Error handling goes here
  }
);

Upvotes: 1

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