Recipe- validating typescript enums

Sometimes you might want to validate that a value is one of the keys or values of a typescript enum. Since typescript enums are compiled to objects, you can use the inside function to validate that the value is one of the keys or values of the enum.

enum Fruits {
  APPLE = 'apple',
  BANANA = 'banana',
  CANTELOPE = 'cantelope',
}

// ...

// If you need the enum by key:
test('fruit', 'fruit is a key of fruits enum', () => {
  // data.fruit is a key of ["APPLE", "BANANA", "CANTELOPE"]
  enforce(data.fruit).inside(Object.keys(Fruits));
});

// If you need the enum by value:
test('fruit', 'fruit is a value of fruits enum', () => {
  // data.fruit is a value of ["apple", "banana", "cantelope"]
  enforce(data.fruit).inside(Object.values(Fruits));
});