枚举类型(enum)

1. 数字类型枚举

enum Direction {
  Up,
  Right,
  Down,
  Left
}

编译成 JS 的结果为

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

2. 字符串类型枚举

enum Direction {
  Up = "Up",
  Right = "Right",
  Down = "Down",
  Left = "Left",
}

编译成 JS 的结果为

var Direction
;(function (Direction) {
  Direction["Up"] = "Up"
  Direction["Right"] = "Right"
  Direction["Down"] = "Down"
  Direction["Left"] = "Left"
})(Direction || (Direction = {}))

3. 异构枚举