String enums in TypeScript

enum.ts

export enum Event1 {
    SIGN_IN_WALL = 'Sign In Wall' as any,
    SIGN_UP = 'Sign Up' as any,
}

{
    const x = Event1.SIGN_UP; // type = Event1
    const y: number = x;
    // Verdict: approach is succint, but incorrectly allows type widening to number.
}

/**/

export namespace Event2 {
    export const SIGN_IN_WALL = 'Sign In Wall';
    export const SIGN_UP = 'Sign Up';
    export type Type = (
        typeof SIGN_IN_WALL |
        typeof SIGN_UP
    );
}

{
    const x = Event2.SIGN_UP; // type = 'Sign Up'
    const y: string = x;
    // Verdict: approach is tedious, but type safe.
}

/**/

// An extension of:
// https://github.com/Microsoft/TypeScript/issues/3192#issuecomment-261720275
function Enum<
    Value extends string
>(...values: Value[]): {[K in Value]: K};
function Enum<
    Shape extends { [key: string]: Value },
    Value extends string
>(definition: Shape): Shape;
function Enum(...values: any[]): object {
    if (typeof values[0] === 'string') {
        const result: any = {};
        for (const value of values) {
            result[value] = value;
        }
        return result;
    } else {
        return values[0];
    }
}

type Enum<T extends object> = T[keyof T];

namespace Enum {    
    export function keys<
        Shape extends { [key: string]: any }
    >(e: Shape): (keyof Shape)[] {
        return Object.keys(e) as (keyof Shape)[];
    }

    export function values<
        Shape extends object
    >(e: Shape): Enum<Shape>[] {
        const result: Enum<Shape>[] = [];
        for (const key of keys(e)) {
            result.push(e[key as string]);
        }
        return result;
    }
}

const Event3 = Enum({
    SIGN_IN_WALL: 'Sign In Wall',
    SIGN_UP: 'Sign Up'
});
type Event3 = Enum<typeof Event3>;

{
    const x = Event3.SIGN_UP; // type = 'Sign Up'
    const y: string = x;
    // Verdict: Succinct *and* type safe.
}