问题中的代码与链接中的代码略有不同。在链接中，
(immediate&&!timeout)在创建新的timout之前要进行检查。之后拥有它会导致即时模式从不触发。我已经更新了答案，以便从链接中注释工作版本。
function debounce(func, wait, immediate) { // 'private' variable for instance // The returned function will be able to reference this due to closure. // Each call to the returned function will share this common timer. var timeout; // Calling debounce returns a new anonymous function return function() { // reference the context and args for the setTimeout function var context = this, args = arguments; // Should the function be called now? If immediate is true // and not already in a timeout then the answer is: Yes var callNow = immediate && !timeout; // This is the basic debounce behaviour where you can call this // function several times, but it will only execute once // [before or after imposing a delay]. // Each time the returned function is called, the timer starts over. clearTimeout(timeout); // Set the new timeout timeout = setTimeout(function() { // Inside the timeout function, clear the timeout variable // which will let the next execution run when in 'immediate' mode timeout = null; // Check if the function already ran with the immediate flag if (!immediate) { // Call the original function with apply // apply lets you define the 'this' object as well as the arguments // (both captured before setTimeout) func.apply(context, args); } }, wait); // Immediate mode and no wait timer? Execute the function.. if (callNow) func.apply(context, args); }}/////////////////////////////////// DEMO:function onMouseMove(e){ console.clear(); console.log(e.x, e.y);}// Define the debounced functionvar debouncedMouseMove = debounce(onMouseMove, 50);// Call the debounced function on every mouse movewindow.addEventListener('mousemove', debouncedMouseMove);
