## 问题 Problem 你只想执行函数一次，把一系列的调用合并成一个单一的调用，在这一些列调用的开头或者结尾执行。 You want to execute a function only once, coalescing multiple sequential calls into a single execution at the beginning or end. ## 方法 Solution 使用一个具名函数： With a named function: ~~~ debounce: (func, threshold, execAsap) -> timeout = null (args...) -> obj = this delayed = -> func.apply(obj, args) unless execAsap timeout = null if timeout clearTimeout(timeout) else if (execAsap) func.apply(obj, args) timeout = setTimeout delayed, threshold || 100 ~~~ ~~~ mouseMoveHandler: (e) -> @debounce((e) -> # Do something here, but only once 300 milliseconds after the mouse cursor stops. 300) someOtherHandler: (e) -> @debounce((e) -> # Do something here, but only once 250 milliseconds after initial execuction. 250, true) ~~~ ## 详解 Discussion 参看John Hann的这篇很赞的文章[debouncing JavaScript methods](http://unscriptable.com/2009/03/20/debouncing-javascript-methods/)。 Learn about [debouncing JavaScript methods](http://unscriptable.com/2009/03/20/debouncing-javascript-methods/) at John Hann’s excellent blog article.