How to Wait for Multiple Promises for All Data Success Callbacks

Question

I have this API call, but I don\'t receive the data in my successCallback in the same order as I send it.

    for (var i = 0; i < data.length; i+         


        

Answer 1

Use $q.all to get all the data in the right order.

var promiseArray = [];
for (var i = 0; i < data.length; i++) {
    var dataPromise = $http.post('/api/bla/blabla', $httpParamSerializer(data[i]))
        .then (function (response) {
             //return data for chaining
             return response.data;
        })
    ;
    promiseArray.push(dataPromise);
}

$q.all(promiseArray).then(function (dataArray) {
     //dataArray will be in original order
     //process results here
}).catch (function (errorResponse) {
     //log error
});

The promiseArray will be created in the correct order. Even though the individual XHR POST requests may not be served in the original order, the $q service will track the promises and fill the data array in the correct order (or resolve rejected on the first error).

The DEMO on JSFiddle.