WinJS check xhr request is cancelled or not

Question

I have few xhr requests as follows,

var promise=[];
promise[0]=.WinJS.xhr({
        type: "POST",
        url: "some url",
        data: somedata,
        headers: { "Content-type": "application/json; charset=utf-8" },
        //  responseType: "json"
    }).then(function(success){}, function(error){});

promise[1]=.WinJS.xhr({
        type: "POST",
        url: "some url",
        data: somedata,
        headers: { "Content-type": "application/json; charset=utf-8" },
        //  responseType: "json"
    }).then(function(success){}, function(error){});
promise[2]=...
.
.
.

Now i will cancel few requests for e.g promise[0], promise[5],

promise[0].cancel();
promise[5].cancel();

Now on join I want to know which all requests are cancelled,

WinJS.Promise.join(promise).done(function(xhr){
//here i should be able to check which requests are cancelled
});

Answer 1

The promise object has a second parameter where you can pass a function that will fire onCalcel.

var aPromise = new WinJS.Promise(init, onCancel);

The WinJS.xhr function work though in a sligtly different way.

The error function is called when the operation is canceled, as well as for any errors that may occur during the download operation.

xhrPromise = WinJS.xhr({ url: "<your choice of URL>" })
    .then(function complete(result) {
        //SUCCESS
    }, 
    function error(result) {
        if (result.name == "Canceled") {
            //CANCELED
        }
        else {
            //OTHER ERRORS
        } 
    });

so if in the error function you return a specific value when it is "Cancel" then you will find this value once all the promises in the join are finished.