Flow Runtime Types

flow-runtime-types.js

type Suit =
  | "Diamonds"
  | "Clubs"
  | "Hearts"
  | "Spades";
  
// Babel transformed into Flow AST:

export const SuitType = {
  type: 'UnionTypeAnnotation',
  types:
   [ { type: 'StringLiteralTypeAnnotation', value: 'Diamonds' },
     { type: 'StringLiteralTypeAnnotation', value: 'Clubs' },
     { type: 'StringLiteralTypeAnnotation', value: 'Hearts' },
     { type: 'StringLiteralTypeAnnotation', value: 'Spades' } ]
}