全局观察者对象与 mixin 的优缺点

Question

创建复杂的 JS 应用程序时，使用触发事件并让所有其他对象订阅的全局观察者对象与在负责触发自己事件的所有对象上混合或原型化 pub/sub 方法有何优缺点？

以具有庄家、玩家和桌子对象的纸牌游戏为例（伪代码如下）

// "Global" observer version

var observer = {
    // publish and subscribe methods defined here
};

dealer.deal = function(cards) {
    // performs logic for dealing cards
    observer.publish('dealer:dealt', cards, this);
};

player.play = function(cards) {
    // performs logic for which card is played
    observer.publish('player:played', cards, this);
};

table.showCards = function(cards, player) {
    // performs logic for showing cards that the dealer dealt
    // or that the player played
};

observer.subscribe('dealer:dealt', table.showCards);
observer.subscribe('player:played', table.showCards);

：

// Pub/sub mixin/prototype version

dealer.deal = function(cards) {
    // performs logic for dealing cards
    this.publish('dealt', cards);
};

player.play = function(cards) {
    // performs logic for which card is played
    this.publish('played', cards);
};

table.showCards = function(cards) {
    // performs logic for showing cards that the dealer dealt
    // or that the player played
};

dealer.subscribe('dealt', table.showCards);
player.subscribe('played', table.showCards);

Answer 1

在您的示例中，两者似乎都是有效的选择，但是在处理动态事件名称（也是动态“发布者”名称）时可以看到差异。

因此，当您需要使用通配符订阅事件时，使用全局发射器是很好的选择。示例：

eventEmitter.subscribe('*:delt', handler);

另一个区别是您可以使用一个变量而不是 2,3 ... N，我相信这对记忆更好。