typescript type from values in array

test.ts

export const extraKeys = [
  'app',
  'title',
  'package',
  'deeplink',
  'url',
  'logo',
  'image',
  'type'
] as const

export type Extra = {
  [key in typeof extraKeys[number]]: string
}


// https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-9.html