throttle
Throttling prevents a function from being called more than once in a given window of time.
节流可防止在给定的时间范围内多次调用某个函数。
节流是阻止函数在指定的时间段内执行超过一次。
用处：更在于基于时间频率的控制，比如1次/秒，1次/10秒
debounce
Debouncing ensures that a function will not be executed until after a certain amount of time has passed since it was last called.
防抖是确保直到上一次调用函数经过一定时间后，该函数才会执行
防抖是确保函数从上次执行经过一定时间后才执行。
用处：确保函数在延迟一段时间才执行，比如监听输入框的输入变化，只有输入停止超过指定时间才会执行，如果等待中间函数再次执行则会继续等待相同时间。
两者区别
区别再于如果函数一直调用，那 debounce 就不会触发，它会一直向后推迟，直到距离上一次执行超过指定时间才执行；而 throttle 是只要到了指定时间函数就可以执行。
一个例子：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Debounce & Throttle demo</title>
</head>
<body>
<button id="btn">点击</button>
<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.21/lodash.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.21/lodash.min.js"></script>
<script type="text/javascript">
window.addEventListener('load', () => {
var btn = document.getElementById('btn')
btn.addEventListener('click', handleClick)
btn.addEventListener('click', clickWithThrottle)
btn.addEventListener('click', clickWithDebounce)
})
var clickWithDebounce = _.debounce(handleDebounce, 500)
var clickWithThrottle = _.throttle(handleThrottle, 500)
var countForDebounce = 0
var countForThrottle = 0
var countForClick = 0
function handleDebounce() {
console.log('debounce click', countForDebounce)
countForDebounce++
}
function handleThrottle() {
console.log('throttle click', countForThrottle)
countForThrottle++
}
function handleClick() {
console.log('click', countForClick)
countForClick++
}
</script>
</body>
</html>
不同频率的点击输出如下：
click 0
throttle click 0
debounce click 0
click 1
throttle click 1
click 2
throttle click 2
click 3
click 4
throttle click 3
debounce click 1
在线的例子 http://demo.nimius.net/debounce_throttle/
10_1.png
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