javascript - 在javascript中将匿名函数作为参数传递

Question

我有以下 javascript 代码:

   EventsManager.prototype.hideContainer = function()
   {
     var that = this;

     var index = that.getNextUnreadEventIndex();
     if(index !== -1)
     {
         EventsManager.animateHideLeft(function() //<--- passing a function as parameter to another function
         {
             var unreadEvent = that.eventsList.splice(index,1)[0];
             unreadEvent.isEventOnFocus = true;

             that.eventsList.push(unreadEvent);
             that.displayLastEvent();
         });  
     }
   }

这是 EventsManager.animateHideLeft() 函数的代码:

EventsManager.animateHideLeft = function(callback)
{
   var p = document.getElementById("eventsContainer");
   var width = parseFloat(p.style.width);

   if(!width || width === "NaN") width = 200;

   if(width <= 10)
   {
      clearTimeout(fr);
      alert(typeof callback); //<-- this shows "undefined"
      callback();
   }
   else
   {
      width = width - 10;

      p.style.width = width + "px";

      fr = setTimeout(function()
      {
          EventsManager.animateHideLeft();
      }, 50);
  }
};

不幸的是，函数 animateHideLeft 没有按预期工作。当我测试 typeof 回调时，它会提示“未定义”。

我怎样才能解决这种困惑，以便获得预期的结果？

Answer 1

看起来您只需要通过 setTimeout 中的调用传递 callback。

fr = setTimeout(function()
{
    EventsManager.animateHideLeft(callback);
}, 50);