$scope.$watch - Array

[{{letter}} ]
[Updated: {{msg.time}}][Shallow watch] letters: {{msg.content}}
[Updated: {{msg2.time}}][Deep watch] letters: {{msg2.content}}
[Updated: {{msg3.time}}][Watch letters[3]] letters[3]: {{msg3.content}}

$scope.$watch - Object

{{obj}}
[Updated: {{msgObj1.time}}][Shallow Watch obj['a']] obj['a']: {{msgObj1.content}}
[Updated: {{msgObj2.time}}][Watch obj['b'] obj['b']: {{msgObj2.content}}