typescript one of array
function stringLiterals<T extends string>(...args: T[]): T[] { return args; }
type ElementType<T extends ReadonlyArray<unknown>> = T extends ReadonlyArray<infer ElementType> ? ElementType : never;
const values = stringLiterals('A', 'B');
type Foo = ElementType<typeof values>;
const v1: Foo = 'A' // This should work
const v2: Foo = 'D' // This should give me an error since 'D' doesn't exist in values