Javascript angularjs array object difference

Question

I have 2 array objects, and I want to get the difference between them as follows:

array1 = [{"name":"MPCC","id":"tool:mpcc"}, {"name":"APP","id":"tool:app"}, {"name":"AII","id":"tool:aii"}, {"name":"VZZ","id":"tool:vzz"}, {"name":"USU","id":"tool:usu"}]

array2 = [{"name":"APP","id":"tool:app"}, {"name":"USU","id":"tool:usu"}]

result = [{"name":"MPCC","id":"tool:mpcc"}, {"name":"AII","id":"tool:aii"}, {"name":"VZZ","id":"tool:vzz"}]

Here is the code:

$scope.initial = function(base, userData){
    var result = [];
    angular.forEach( base, function(baseItem) {
        angular.forEach( userData, function( userItem ) {
            if ( baseItem.id !== userItem.id ) {
                if (result.indexOf(baseItem) < 0) { 
                    result.push(baseItem);
                }
            }
        });
    });
    return result;
}
$scope.initial(array1, array2);

The problem with the above code is that I am not getting the desired result. Please let me know what is going wrong.

Answer 1

This is not related to Angular.

You can do something like this:

var result = array1.filter(function(item1) {
  for (var i in array2) {
    if (item1.id === array2[i].id) { return false; }
  };
  return true;
});

Or with ES6 syntax:

var result = array1.filter(i1 => !array2.some(i2 => i1.id === i2.id));

Answer 2

I think this is not related to Angular. You are looking for an algorithm to calculate the difference between two sets.

The topic has already been discussed. You may also be interested in this underscore plugin