格式化文件大小

sizeFormatter(value) {
    if (value === null || value === undefined || value === '') return ''
    if (value === 0) return '0 B';

    const sizes = ['B', 'KB', 'MB', 'GB', 'TB'];
    const i = parseInt(Math.floor(Math.log(value) / Math.log(1024)));

     return parseFloat((value / Math.pow(1024, i)).toFixed(1)) + ' ' + sizes[i];
},