编辑代码

const unitList=['B','KB','MB','GB','TB','PB'],
    unitSizeList=unitList.map((item,i)=>Math.pow(1024,i));

const formatFileSize=(size)=>{
    if(!size){
        return '0B';
    }
    let index=Math.floor(size.toString().length/3);
    if(index>=unitList.length){
        index=unitList.length-1;
    }
    let targetSize=parseInt(size/unitSizeList[index]*100)/100;
    return targetSize+unitList[index]
}

console.log(formatFileSize(2358))