angular encode part of $scope to json - json

Question

I'm working with angular and have most of my api functioning, but I'm having trouble with a put function. My server is hosted by an arduino and can't receive all the data sent by the json stringify.
How to make a JSON obj with only certain $scope data?
This is what I've got so far, with 'chanObj'. The alert returns in some tests "undefined", and on other tests an empty object at the end of the scope.
$scope.setpointClk = function(channel, setpoint) {
var channels = JSON.stringify($scope.channels); //original obj to big
var chanObj = {setPoint : channel.setPoint, name : channel.name
}; //try to create a selected content obj
alert(chanObj);
service.putChannels(channels, function() {
$scope.init();
});
}
channels: [{name: null, canal: "0", status: false, temperature: 19.94, setPoint: 0, permission: false,…},…]
0: {name: null, canal: "0", status: false, temperature: 19.94, setPoint: 0, permission: false,…}
1: {name: null, canal: "1", status: false, temperature: 20.37, setPoint: 5, permission: false,…}
2: {name: null, canal: "2", status: false, temperature: 0, setPoint: 5, permission: false, percentOut: 0}
3: {name: null, canal: "3", status: false, temperature: 0, setPoint: 5, permission: false, percentOut: 0}
4: {name: null, canal: "4", status: false, temperature: 19.94, setPoint: 5, permission: false,…}
5: {name: null, canal: "5", status: false, temperature: 19.87, setPoint: 5, permission: false,…}
6: {name: null, canal: "6", status: false, temperature: 19.98, setPoint: 5, permission: false,…}
7: {name: null, canal: "7", status: false, temperature: 19.96, setPoint: 5, permission: false,…}
8: {name: null, canal: "8", status: false, temperature: -50, setPoint: 5, permission: false,…}
9: {name: null, canal: "9", status: false, temperature: -50, setPoint: 5, permission: false,…}

Answer 1

You should create your chanObj without first calling the JSON.stringify function. Because that would convert your $scope.channels into a string.
E.g. on how to create your chanObj with specific properties from your $scope.channels
$scope.setpointClk = function(channel, setpoint) {
...
var chanObj = {
setPoint: $scope.channels.setPoint,
name: $scope.channels.name
};
...
}

Answer 2

Just create a new object and pass that to the put call, like you have with the chanObj object, pass that to the put.
If you have a lot of properties to maintain, you could do something like this:
var propertiesToCopy = ["setPoint", "name", "foo", "bar"],
cutdownVersion = {};
for(var key in propertiesToCopy) {
cutdownVersion[key] = channels[key];
}
Then pass the cutdownVersion object to the put call.