Hashchange事件侦听器在事件处理程序附加到事件之前侦听

Question

我有以下代码

console.info('checking if url contains hash');
if (!location.hash) {
  console.warn('if-block replacing hash to empty!');
  location.href = '#';

  // Running route() to trigger Router.otherwise()
  console.info('running route() from if-block(hash doesn\'t exist)');
  route(location.hash.slice(1));
} else {
  // URL contains a hash. Running Router.when() to load template
  console.info('running route() from else-block(hash already present in url)');
  route(location.hash.slice(1));
}

// Bind hashchange-event to window-object... duh
console.info('binding hashchange event');
$(window).on('hashchange', function () {
  console.info('running route() from hashchange');
  route(location.hash.slice(1));
});

显然，事件监听器附加在else-if块之后。我的控制台输出验证了这个

2015-02-13 12:51:14.281 main.js:69 checking if url contains hash
2015-02-13 12:51:14.284 main.js:71 if-block replacing hash to empty!
2015-02-13 12:51:14.290 main.js:75 running route() from if-block(hash doesn\'t exist)
2015-02-13 12:51:16.677 main.js:84 binding hashchange event
2015-02-13 12:51:16.678 main.js:86 running route() from hashchange

看起来事件监听器以某种方式获取先前触发的hashchange事件 仅当网址为example.com而非example.com/#时才会出现此问题。如果您在进入网站时网址中缺少/或/#，则会触发此现象。

编辑：我遇到的问题是hashchange事件监听器在它甚至监听哈希变化之前就会触发。我想知道这是否正常。

另一个编辑： 一个更清晰的示例显示，当我第一次运行getEventListeners(window)时，没有监听器附加到hashchange事件。尽管如此，当我添加事件监听器时，它会选择之前触发的hashchange

我在这里遗漏了什么或者发生了什么事吗？ 有没有办法绕过这个？

Answer 1

让我们将代码简化为

location.hash = 'foobar';
window.onhashchange = function() {
  document.body.innerHTML = 'You should not see me. But you do :(';
};

要解决此问题，您可以使用setTimeout来延迟添加事件处理程序：

location.hash = 'foobar';
setTimeout(function(){ // Delayed code
  window.onhashchange = function() {
    document.body.innerHTML = 'You should not see me. And you do not :)';
  };
}, 0);