In using frozen objects to create enums, it seems the literal value is not inferred to the type of that object's property.

In the following example, when using the $Values utility we get a union of the values, as expected ('THING' | 'THING_TWO'), but when using typeof to get the type of one of these properties, we get a type of string. I'd expect to get the string literal type instead.

const ENUM = Object.freeze({
    THING: 'THING',
    THING_TWO: 'THING_TWO',
});

const notAThing: typeof ENUM.THING = 'NOT_A_THING' // no error

const isAThing: $Values<typeof ENUM> = 'IS_A_THING' // Cannot assign `'IS_A_THING'` to `isAThing` because string [1] is incompatible with enum [2].

Try Flow

Of course, typing each property individually works, but I'd expect Object.freeze() to produce the same output. Is there another way around this?