createObjectFromTuple.ts

type ObjectFromTuple<T extends string[]> =
  FlattenObject<  // 5. Делаем объект плоским
    ToIntersect<  // 4. Union to Intersection
      {           // 2. { [key]: { [value]: value } }
        [K in keyof T]: T[K] extends string
          ? Record<T[K], T[K]> // 1. { [value]: value }
          : never
       }[number]  // 3. { [key]: { [value]: value } } -> { [value]: value } & { [value]: value }
    >
  >
;

function createObjectFromTuple<T extends string[]>(...tuple: T) {
  return tuple.reduce((obj, key) => {
    obj[key] = key;
    return obj;
  }, {} as ObjectFromTuple<T>);
}

// Проверяем
const result = createObjectFromTuple('foo', 'bar', 'qux');
// typeof result:
// {
//    foo: "foo";
//    bar: "bar";
//    qux: "qux";
// }