jquery“on”事件

Question

设置：

handlerA & handlerB listen for event1, while handlerC listens for event2

执行：

1. event1 is sent (handlers A & B are listening)
2. handlerA receives it, and along it's codepath sends event2
3. handlerC receives event2
4. handlerB receives event1

问题：如果'on'事件应该是异步的，那么在handlerC收到event2之前，handlerB不应该接收event1吗？有人可以向我解释一下吗？

console.clear();

window.EventDispatcher = {
  send: function(type, payload) {
    $(EventDispatcher).trigger({
      type: type,
      payload: payload
    });
  }
};

//---- SEND EVENT ----
$(function() {
  $('#sendEventBtn').on('click', function() {
    console.log('sending event1 to A and B...')
    EventDispatcher.send('event1')
  })
})

$(EventDispatcher).on('event1', handlerA);
$(EventDispatcher).on('event1', handlerB);
$(EventDispatcher).on('event2', handlerC);

function handlerA() {
  console.log('handlerA received event1');
  console.log('handlerA sending event2');
  EventDispatcher.send('event2')
}

function handlerB() {
  console.log('handlerB received event1');
}

function handlerC() {
  console.log('handlerC received event2');
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button id='sendEventBtn'>Send Event</button>

这是一个掠夺者：http://plnkr.co/edit/Ux0kL3d5Hul8IopUXeRW?p=preview

Answer 1

您正在寻找的词是“非阻塞”＆amp;这不是“意外”的行为，如果来自handlerA的event2首先被触发，那么显然handlerC会首先得到它，它的全部都是关于时间的。简而言之，如果到达第4行，如果handlerA已经完成，那么handlerC将接收该事件。

function handlerA() {
    console.log('handlerA received event1');
    console.log('handlerA sending event2');
    EventDispatcher.send('event2')
}

  

将event1发送到A和B ......

     

handlerA收到了event1

     

handlerA发送event2

     

handlerC收到了event2

     

handlerB收到了event1

现在有一些延迟（了解更多关于setTimeout with 0）事件2＆amp;你会看到。

function handlerA() {
    console.log('handlerA received event1');
    setTimeout(function(){
       console.log('handlerA sending event2');
       EventDispatcher.send('event2');           
    }, 0);
}

  

将event1发送到A和B ......

     

handlerA收到了event1

     

handlerB收到了event1

     

handlerA发送event2

     

handlerC收到了event2