1.實(shí)現(xiàn)一個防抖函數(shù)
function debounce (fn, delay) {
// 利用閉包保存定時器
let timer = null
return function () {
let context = this
let arg = arguments
// 在規(guī)定時間內(nèi)再次觸發(fā)會先清除定時器后再重設(shè)定時器
clearTimeout(timer)
timer = setTimeout(function () {
fn.apply(context, arg)
}, delay)
}
}
function fn () {
console.log('防抖')
}
addEventListener('scroll', debounce(fn, 1000))
2.實(shí)現(xiàn)一個節(jié)流函數(shù)
function throttle (fn, delay) {
// 利用閉包保存時間
let prev = Date.now()
return function () {
let context = this
let arg = arguments
let now = Date.now()
if (now - prev >= delay) {
fn.apply(context, arg)
prev = Date.now()
}
}
}
function fn () {
console.log('節(jié)流')
}
addEventListener('scroll', throttle(fn, 1000))
