谁能给我一个简单的解释,关于节流和debounging函数之间的区别,以限制速率的目的。
在我看来,两者的作用是一样的。我查看了这两个博客来找出答案:
http://remysharp.com/2010/07/21/throttling-function-calls
http://benalman.com/projects/jquery-throttle-debounce-plugin/
谁能给我一个简单的解释,关于节流和debounging函数之间的区别,以限制速率的目的。
在我看来,两者的作用是一样的。我查看了这两个博客来找出答案:
http://remysharp.com/2010/07/21/throttling-function-calls
http://benalman.com/projects/jquery-throttle-debounce-plugin/
当前回答
Throtle只是debounce的包装器,它使debounce在一段时间内调用传递的函数,如果debounce在一段时间内延迟函数调用,该时间大于Throtle中指定的时间。
其他回答
debound允许您管理函数可以接收的调用频率。它将发生在给定函数上的多个调用组合在一起,以便忽略在特定时间持续时间到期之前发生的重复调用。从根本上说,deboundation确保了一个可能发生多次的事件只发送了一个信号。
节流将函数接收的调用频率限制在固定的时间间隔内。它用于确保目标函数的调用频率不会超过指定的延迟。节流是降低重复事件的速率。
这实际上是限制一个事件的方法。例如,如果你正在监听onclick事件,如果它是常规的,它将监听你所做的每一次点击。
如果你使用Throttle,它会在你想要监听事件的时间之间设置一个间隔,例如每秒钟监听一次点击。
Debounce的限制更大,它只会在事件开始或结束时触发自己。例如,你正在滚动,你使用Debounce,它只会在你开始和结束滚动时触发。
这里真正重要的是,用最简单的话说:如果你有一些连续重复一段时间的操作(如鼠标移动,或页面大小调整事件),你需要运行一些函数来响应,但你不想对每个操作都做出反应(因为这可能会损害性能),你有两个选择:
debounce - you skip all incoming actions, except the last one (the 'last one' is defined by the 'wait' time period you set for debounce function, for example, 2s - it will consider that actions flood stopped, if no actions were taken for 2s, and then it will react. This strategy is reasonable if you don't care about regular updates, you just need to react at least once. throttle - if you want to react 'on schedule', to make regular updates even if actions flood is endless, you make your function run at regular intervals (no more often, then the specified time interval), for example 2s throttling will mean that your response will be executed an once if action is taken, but no less then 2s after that. So with continuous actions flood your response will be run on 0s, 2s, 4s, 6s, 8s...
防反跳:
如果函数没有在间隔内被调用,则在间隔后执行函数。
节流:
以固定的时间间隔执行函数n次。
我个人认为反弹比油门更难理解。
因为这两个函数都可以帮助您延迟和降低某些执行的速度。假设您正在调用由throttle/debounce反复返回的装饰函数…
节流:在指定的时间段内,原函数最多被调用一次。 Debounce:在指定的时间后,调用方停止调用被修饰的函数后,将调用原始函数。
我发现debounce的最后一部分对于理解它试图实现的目标至关重要。我还发现_.debounce的旧版本实现有助于理解(由https://davidwalsh.name/function-debounce提供)。
// Returns a function, that, as long as it continues to be invoked, will not
// be triggered. The function will be called after it stops being called for
// N milliseconds. If `immediate` is passed, trigger the function on the
// leading edge, instead of the trailing.
_.debounce = function(func, wait, immediate) {
var timeout;
return function() {
var context = this, args = arguments;
var later = function() {
timeout = null;
if (!immediate) func.apply(context, args);
};
var callNow = immediate && !timeout;
clearTimeout(timeout);
timeout = setTimeout(later, wait);
if (callNow) func.apply(context, args);
};
};
这是一个牵强的比喻,但也许也有帮助。
你有一个叫Chatty的朋友,他喜欢通过IM和你聊天。假设当她说话时,她每5秒发送一条新消息,而你的即时通讯应用程序图标上下跳动,你可以…
Naive approach: check every message as long as it arrives. When your app icon bounces, check. It's not the most effective way, but you are always up-to-date. Throttle approach: you check once every 5 minutes (when there are new ones). When new message arrives, if you have checked anytime in the last 5 minutes, ignore it. You save your time with this approach, while still in the loop. Debounce approach: you know Chatty, she breaks down a whole story into pieces, sends them in one message after another. You wait until Chatty finishes the whole story: if she stops sending messages for 5 minutes, you would assume she has finished, now you check all.