性能优化

//防抖（input输入返回值）
input.addEventListener(‘keyup‘, debounce(()=>{
    console.log(input.value)
}),600)

function debounce(fn,delay=500){
    let timer = null;return function(){
        if (timer) {
            clearTimeout(timer)
        }
        timer = setTimeout(() => {
            fn.apply(this,arguments)
            timer = null
        }, delay);
    }
}

//节流（拖拽情况下返回坐标信息）
const div2 = document.getElementById(‘div2‘)
let timer = null ;
div2.addEventListener(‘drag‘, throttle((e)=>{
    console.log(e)
},200))

function throttle(fn, delay = 500){
    let timer = null;
    return function(){
        if (timer) {
            return
        }
        timer = setTimeout(() => {
            fn.apply(this, arguments)
            timer = null
        }, delay);
    }
}