Wait for Angular Factory Resource Call to complete inside for loop

Question

Hi there I've been trying to use promise technique to wait for the execution of calls inside a for loop.However I am not able to hold on.

"return mainArr" gives undefined

//export CSV

Loop

//Assumes data is a json object list.

function getCustomData(data){

            var mainArr=[];
            for (var i = 0; i < data.length; i++) {
                var obj={};
                obj.word = $('#type-ahead-input').val();
                obj.synonym = data[i].word;
                obj.similarityCount = (data[i].similarityCount).toFixed(2);
                obj.emailCount = data[i].occuranceCount;
                obj.synonymlist = getSynonymList(data[i].word);
                mainArr.push(obj);

            }
            return mainArr;
        }
        function getSynonymList(inputWord){
            return WordService.getSynonymList({
                ids : inputWord
            }).$promise
                    .then(function($response) {
                        var output = $response;

                        var wordList =[];
                        for (var i = 0; i < output.length; i++) {
                            wordList.push(output[i].word);
                        }

                        return wordList;
                    });
        }

Factory Resource Call Signature

getSynonymList : {

        method : 'GET',
        isArray: true,
        async  : false,
        url : appRoot + '/synonym',
        params : {
            word : '@word'
        }
    },

The return from an onFulfilled callback in the $promise.then method results in a $q promise, not data. Using the same name, getSynonymList, for a service that returns a $resource object, and a function that returns a promise makes your code confusing and difficult to understand. — georgeawg
– georgeawg, Commented Jan 22, 2016 at 19:11

sjokkogutten · Accepted Answer · 2016-01-22 20:00:13Z

1

You need to push the value into an promises array, and use $q.all() to resolve multiple promises

function getCustomData(data){

        var promises = []; // an array of promises
        for (var i = 0; i < data.length; i++) {
             // rest of you code here

            var promise = $q.when(data);  // returns a promise             
            promises.push(obj);
        }

        return $q.all(promises);
    }

then you can call the return values using callback

myservice.getCustomerData(data).then(
  function successcallback(returnvalue){
    console.log(returnvalue);
  }, 
  function errorcalback(error){
    console.log(returnvalue);
}

This applies to both your functions, since you are using loops. (Note that I have not implemented the above code, but should provide you with an outline)

edited Jan 22, 2016 at 20:00

answered Jan 22, 2016 at 19:16

sjokkogutten

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