No error on value outside TypeScript enum

Question

Was hoping this might produce a compile time error but I guess I have just misunderstood how enums work...

enum SortDirection {
    ascending = 1,
    descending = -1
}
type IndexSpec = {[index: string]: SortDirection};

var i: IndexSpec = {thing: 3};  // no compile time error

Answer 1

All numeric values are considered value enum values.

This is allowed because there's no distinction between flag and non-flag enums:

enum MyFlags {
  Cool = 0x1,
  Awesome = 0x2,
  Neat = 0x4
}

var i: MyFlags = 5; // Cool | Neat