var collection = new Backbone.Collection([
{key:1,name: "Tim", age: 5},
{key:2,name: "Ida", age: 26},
{key:3,name: "Rob", age: 55}
]);
i am going to add the model
{key:4,name: "Rob", age: 55}
Here since the key is different, backbone will not give an error. How do I check for an existing model in the collection before adding?