//节流 -- 立即执行回调
function throttle(callback,wait){
    let start = 0;
    return function(e){
        let now = Date.now()
        if(now - start >= wait){
            callback.call(this,e)
            start = now
        }
    }
}
//防抖 -- 事件触发时不会立即触发回调
function debounce(callback,time){
    let timer = null
    return function(e){
        if(timer){
            clearTimeout(timer)
        }
        timer = setTimeout(()=>{
            callback.call(this,e)
            timer = null
        },time)
    }
}