Link: 

 

Example: 

.service('UserPresenter', function(UserConstants){  var typeFromId = _.memoize(function(typeId){    var obj = _.findWhere(UserConstants.types, { value: typeId});    return obj ? obj.display : '';      });    return {    fullName: function(user){      return user.firstName + ' ' + user.lastName;    },    type: function(user){      return typeFromId(user.typeId);    }  };})

 

It is useful when you want to find something like userId, then you can use memoize() to cache the result.