以下内容是否会使对象满足枚举在JavaScript中的所有特性？类似于：
my.namespace.ColorEnum = {
RED : 0,
GREEN : 1,
BLUE : 2
}
// later on
if(currentColor == my.namespace.ColorEnum.RED) {
// whatever
}
还是有其他方法可以做到这一点？
当前回答
一种快速而简单的方法是：
var Colors = function(){
return {
'WHITE':0,
'BLACK':1,
'RED':2,
'GREEN':3
}
}();
console.log(Colors.WHITE) //this prints out "0"
其他回答
创建对象文字：
const Modes = {
DRAGGING: 'drag',
SCALING: 'scale',
CLICKED: 'click'
};
var ColorEnum = {
red: {},
green: {},
blue: {}
}
您不需要确保不以这种方式将重复的数字分配给不同的枚举值。一个新对象被实例化并分配给所有枚举值。
您只需要使用object.freeze（<your_object>）创建一个不可变的对象：
export const ColorEnum = Object.freeze({
// you can only change the property values here
// in the object declaration like in the Java enumaration
RED: 0,
GREEN: 1,
BLUE: 2,
});
ColorEnum.RED = 22 // assigning here will throw an error
ColorEnum.VIOLET = 45 // even adding a new property will throw an error
你的答案太复杂了
var buildSet = function(array) {
var set = {};
for (var i in array) {
var item = array[i];
set[item] = item;
}
return set;
}
var myEnum = buildSet(['RED','GREEN','BLUE']);
// myEnum.RED == 'RED' ...etc
我编写了enumeranjs一个非常小的库来解决这个问题，它确保了类型安全，允许枚举常量从原型继承，保证枚举常量和枚举类型是不可变的+许多小特性。它允许重构大量代码，并在枚举定义中移动一些逻辑。下面是一个示例：
var CloseEventCodes = new Enumeration("closeEventCodes", {
CLOSE_NORMAL: { _id: 1000, info: "Connection closed normally" },
CLOSE_GOING_AWAY: { _id: 1001, info: "Connection closed going away" },
CLOSE_PROTOCOL_ERROR: { _id: 1002, info: "Connection closed due to protocol error" },
CLOSE_UNSUPPORTED: { _id: 1003, info: "Connection closed due to unsupported operation" },
CLOSE_NO_STATUS: { _id: 1005, info: "Connection closed with no status" },
CLOSE_ABNORMAL: { _id: 1006, info: "Connection closed abnormally" },
CLOSE_TOO_LARGE: { _id: 1009, info: "Connection closed due to too large packet" }
},{ talk: function(){
console.log(this.info);
}
});
CloseEventCodes.CLOSE_TOO_LARGE.talk(); //prints "Connection closed due to too large packet"
CloseEventCodes.CLOSE_TOO_LARGE instanceof CloseEventCodes //evaluates to true
枚举基本上是一个工厂。
此处提供完整记录的指南。希望这有帮助。
