object-ref-watch.js

scope.$watch('obj1', function callback(newValue) {
  console.log('obj1: ', newValue);
});

// (when initialized) prints out: undefined

$timeout(function() {
  scope.obj1 = {name: 'jonathan'}; // prints out: {name: 'jonathan'}
});

$timeout(function() {
  scope.obj1.name = 'michael'; // no "change" registered, no print out
}, 500);

$timeout(function() {
  scope.obj1.age = 30; // no "change" registered, no print out
}, 1000);

$timeout(function() {
  // it's a new object! 
  scope.obj1 = {name: 'jonathan'}; // prints out: {name: 'jonathan'}
}, 1500);