Typescript: check if value is contained in type

Question

I have problem with defined types and checking if a value is contained in that type.

Here is my example:

these are the types:

export type Key         


        

Answer 1

You could use a string enum.

export enum Keys = {
  Features = 'features',
  Special = 'special',
}

// Compare it
if (currentKey === Keys.Special) { console.log('Special key is set'); }

In order to check if your value is defined in the predefined Enum at all you can do:

if (currentKey in Keys) { console.log('valid key'); }