Dojo ItemFileReadStore or store that implements Identity API

When using stores that implement the Identity API – json passed to store has a identifier attribute – make sure that this is maintained as unique. Otherwise, it throws an error

dojo.data.ItemFileReadStore: The json data as specified by: [/serverURL/that/returns/json/data] is malformed. Items within the list have identifier: [displayLabel]. Value collided: [<Actual value that collided >]