enum.ts

namespace Ext {
    export enum A {
      One = 'one',
      Two = 'two',
      Three = 'three',
    }

    export namespace B {
        export type Type = typeof One | typeof Two | typeof Three
        export const One = 'one'
        export const Two = 'two'
        export const Three = 'three'
    }

    const one = 'one'
    const two = 'two'
    const three = 'three'

    export const C = {
        One: one as typeof one,
        Two: two as typeof two,
        Three: three as typeof three,
    }
    export type C = typeof C[keyof typeof C]
}

function a(p: Ext.A) {
    return 'a'
}

a('one')
a(Ext.A.One)

function b(p: Ext.B.Type) {
    return 'b'
}

b('one')
b(Ext.B.One)

function c(p: Ext.C) {
    return 'c'
}

c('one')
c(Ext.C.One)