OrderedDictionaryTKey, TValueKeyCollectionEnumerator Structure

public struct Enumerator : IEnumerator<TKey>, 
	IDisposable, IEnumerator

Public Structure Enumerator
	Implements IEnumerator(Of TKey), IDisposable, IEnumerator

public value class Enumerator : IEnumerator<TKey>, 
	IDisposable, IEnumerator

[<SealedAttribute>]
type Enumerator = 
    struct
        inherit ValueType
        interface IEnumerator<'TKey>
        interface IDisposable
        interface IEnumerator
    end

JavaScript supports the use of structures, but not the declaration of new ones.