promiseWhile demo

promiseWhile.js

function promiseWhile(condition, body) {
    var dfd = $.Deferred();

    function loop() {
        if (!condition()) return dfd.resolve();
        body.apply(this, arguments)
        .done(loop)
        .fail(dfd.reject);
    }
    //call loop async
    setTimeout(loop, 0);
    // The promise
    return dfd.promise();
}

function sum(id, houses){
    var sumCandidate6 = 0;
    var sumCandidate7 = 0;
    var noDataHouseNum = 0;

    for (var i = 0; i < houses.length; i++) {   
        var house = houses[i];
        sumCandidate6 += house.get('candidate6');
        sumCandidate7 += house.get('candidate7');
        if(house.get('candidate6') + house.get('candidate7') === 0){
            noDataHouseNum++;
        }
    }
    return {
        districtId: id, 
        candidate6: sumCandidate6, 
        candidate7: sumCandidate7, 
        noDataHouseNum: noDataHouseNum, 
        totalHouseNum: houses.length
    };
}

var districIdList = [];
//generate list
for(var index = 0 ; index < 12 ; index++){
    districIdList.push((6300100 + index*100).toString());
}

//prepare result list
var districtVoteList =[];

promiseWhile(function () { 
    return districIdList.length > 0;
}, function (results) {
    var dfd = $.Deferred();
    var districtId = districIdList[0];
    if(results){
        console.log("districtId : " + districtId);
        districtVoteList.push(
            sum(districtId, results)
        );
        //remove first element
        districIdList.shift();
        //select next query id
        districtId = districIdList[0];
    } else {
        console.log('---start promise while---')
    }
   
    //fake query find callback 
    setTimeout(function(){
        function House(attrs){
            this.attrs = attrs;
            this.get = function(name) {
                return this.attrs[name];
            }
        }
        dfd.resolve([
            new House({
                candidate6: 1,
                candidate7: 2
            }),
            new House({
                candidate6: 1,
                candidate7: 2
            }),
            new House({
                candidate6: 0,
                candidate7: 0
            }),
        ]);
    }, 10);

    // query.equalTo("districtId", districtId);
    // return query.find();
    return dfd.promise();
})
.done(function() {
    console.log('all done');
    console.log(districtVoteList);
});