Type Lookup
Sometimes, you may want to lookup for a type in a union to by their attributes.
In this challenge, we would like to get the corresponding type by searching for the common type
field in the union Cat | Dog
. In other words, we will expect to get Dog
for LookUp<Dog | Cat, 'dog'>
and Cat
for LookUp<Dog | Cat, 'cat'>
in the following example.
interface Cat { type: 'cat' breeds: 'Abyssinian' | 'Shorthair' | 'Curl' | 'Bengal' } interface Dog { type: 'dog' breeds: 'Hound' | 'Brittany' | 'Bulldog' | 'Boxer' color: 'brown' | 'white' | 'black' } type MyDogType = LookUp<Cat | Dog, 'dog'> // expected to be `Dog`