gistfile1.js

result = [{a:null,b:2}, {b:4,c:null}];
result.forEach(function (el) {
  var keys = Object.prototype.keys(el);
  keys.forEach(function (el2) {
    if (el[el2] === null) {
      delete el[el2];
    }
  });
});

var result = Object.freeze([{a:null,b:2}, {b:4,c:null}]);
resclone = [];
result.forEach(function (el) {
  var kels = Object.keys(el);
  var arr = {};
  kels.forEach(function (kel) {
    if (el[kel] !== null) {
      arr[kel] = el[kel];
    }
  });
  resclone.push(arr);
});
resclone;