Enum 編譯

// 編譯前 (TypeScript)
enum Direction {
  Up,    // 預設值為 0
  Down,  // 1
  Left,  // 2
  Right, // 3
}

// 編譯後
var Direction;
(function (Direction) {
    Direction[Direction["Up"] = 0] = "Up";
    Direction[Direction["Down"] = 1] = "Down";
    Direction[Direction["Left"] = 2] = "Left";
    Direction[Direction["Right"] = 3] = "Right";
})(Direction || (Direction = {}));

// 編譯前 (TypeScript)
enum Status {
  Success = "SUCCESS",
  Failure = "FAILURE",
}

// 編譯後 (JavaScript)
"use strict";
var Status;
(function (Status) {
    Status["Success"] = "SUCCESS";
    Status["Failure"] = "FAILURE";
})(Status || (Status = {}));

// 編譯前 (TypeScript)
const enum Color {
  Red = 1,
  Green,
  Blue,
}
let c = Color.Green;

// 編譯後 (JavaScript)
"use strict";
var c = 2;