Pass an array as a query string in AngularJS? - angularjs

Question

I have a form with firstname, lastName, zipcode..etc, in addition to multi value input, in which the user check many checkboxes (which will be an array).
I wanna submit this form using angular js $http, and pass them as a query string, currently I have it like this:
firstName=test&lastName=test&homeZip=44551&carInterested=honda%2Cford%2Ctoyota
but my requirement is to be like this:
firstName=test&lastName=test&homeZip=44551&carInterested=honda&carInterested=ford&carInterested=toyota
here is my code:
$scope.signUp = function() {
$scope.formData.carInterested= $scope.selection
console.log ($scope.formData);
$http({
method : 'POST',
url : '/sonmeUr/../',
transformRequest: transformRequestAsFormPost,
data : $scope.formData
})
.success(function(data) {
console.log(data);
});
}
and in my service I have this:
.factory( "transformRequestAsFormPost", function() {
function transformRequest( data, getHeaders ) {
var headers = getHeaders();
headers[ "Content-type" ] = "application/x-www-form-urlencoded; charset=utf-8";
return( serializeData( data ) );
}
return( transformRequest );
function serializeData( data ) {
if ( ! angular.isObject( data ) ) {
return( ( data == null ) ? "" : data.toString() );
}
var buffer = [];
for ( var model in data ) {
if ( ! data.hasOwnProperty( model ) ) {
continue;
}
var value = data[ model ];
buffer.push(
encodeURIComponent( model ) +
"=" +
encodeURIComponent( ( value == null ) ? "" : value )
);
}
var source = buffer
.join( "&" )
.replace( /%20/g, "+" )
;
return( source );
}
}
);