Types from both keys and values of object in Typescript

Question

I have two sets of string values that I want to map from one to the other as a constant object. I want to generate two types from that mapping: one for keys and one for val

Answer 1

I know that it may not be related, but for my usecase, I reached this question because I wanted to create a type based on an object or array. So I just thought it may be useful for someone with the same usecase reaching this question to use enums: You can simply define an enum like this:

enum Arrow {
  Up,
  Down,
  Left,
  Right
}

You can read more about them here and here.

You can now use this enum as a type:

type Props = {
  arrow: Arrow
}

const Component = (props: Props) => {
  switch(props.arrow) {
    case Arrow.Up:
      // go-up
    case Arrow.Down:
      // go-down
    ...
  }

}

and you can use it in your components: