enum OnOff { ON, OFF }

let sw: OnOff = OnOff.ON;

sw = OnOff.OFF;

//なぜか数値を設定してもエラーにならない
sw = 123;

enum Direction {
	Up    = 1,
	Down  = 2,
	Left  = 3,
	Right = 4
}

let d: Direction = Direction.Up;

if (d == Direction.Up) console.log('Up');

if (d == Direction.Up.valueOf())   console.log('Up');
if (d == Direction.Down.valueOf()) console.log('Down');

if (d == 1) console.log('Up');
if (d == 2) console.log('Down');

console.log(d); //1

Up
Up
Up
1