Enum inside class (TypeScript definition file)

Here's my solution.

program.ts:

enum Status {
    Deleting,
    Editing,
    Existing,
    New
}

export class Program {
    static readonly Status = Status;
    readonly Status = Program.Status;

    title: string;

    status: Status;

    constructor(init?: Partial<Program>) {
        Object.assign(this, init);
    }
}

---

Usage:

let program = new Program({ title: `some title` });

program.status = Program.Status.New;

or

program.status = program.Status.New;

---

Added benefit for Angular 2+ users: this can be used in templates

<div *ngIf="program.status === program.Status.New">
  Only display if status of the program is New
</div>

I think that this stuff with module augmentation is a very hacky and non-intuitive way* of doing things, so consider this:

export module Graphics
{
    enum State
    {
        STATE_IDLE,
        STATE_LOADING,
        STATE_READY,
        STATE_ERROR
    }

    export class Image
    {
        constructor() { }
        public static readonly State = State;
    }
}

//...

let imgState = Graphics.Image.State.STATE_ERROR;

That is, just declare the enum in the scope of the class that you want to add it to without exporting it, then expose it through a member of the class.

_{* Which in regards of structuring and organization of code is BAD, even if it technically works.}

Update

declare module Lib
{
    enum State
    {
        STATE_IDLE,
        STATE_LOADING,
        STATE_READY,
        STATE_ERROR
    }

    class ImageClass
    {
        constructor();
        public Prop: any;
    }

    export interface Graphics
    {
        Image: typeof State & ImageClass & (new () => typeof State & ImageClass);
    }
}

declare var Graphics: Lib.Graphics;

Then you get typing like:

var someEnum = Graphics.Image.STATE_ERROR;
var image = new Graphics.Image();
var anotherEnum = image.STATE_IDLE;

I also bumped into this problem recently. This is what I am currently using as a solution:

// File: Image.ts

class Image
{
    constructor()
    {
        this.state = Image.State.Idle;
    }

    state: Image.State;
}

module Image
{
    export enum State
    {
        Idle,
        Loading,
        Ready,
        Error
    }
}

export = Image;

Then in the place where I'm using the class and its enum:

import Image = require("Image");

let state = Image.State.Idle;
let image = new Image();
state = image.state;

This seems to work fine (even though I don't consider it as the expected way to do this kind of thing).

Hopefully there will be a way in TypeScript to do it this way:

class Image
{
    enum State
    {
        Idle,
        Loading,
        Ready,
        Error
    }

    constructor()
    {
        this.state = State.Idle;
    }

    state: State;
}

export = Image;

I think the following is an improvement on KoenT's solution:

export class Image
{
    constructor ()
    {
        this.state = Image.State.Idle;
    }

    state: Image.State;
}

export namespace Image
{
    export enum State
    {
        Idle,
        Loading,
        Ready,
        Error
    }
}

The advantage being that you can leverage named imports:

import {Image} from './image';
let img = new Image()
img.state = Image.State.Error