我得到这段代码通过PHP隐蔽大小字节。
现在我想使用JavaScript将这些大小转换为人类可读的大小。我尝试将这段代码转换为JavaScript,看起来像这样:
function formatSizeUnits(bytes){
if (bytes >= 1073741824) { bytes = (bytes / 1073741824).toFixed(2) + " GB"; }
else if (bytes >= 1048576) { bytes = (bytes / 1048576).toFixed(2) + " MB"; }
else if (bytes >= 1024) { bytes = (bytes / 1024).toFixed(2) + " KB"; }
else if (bytes > 1) { bytes = bytes + " bytes"; }
else if (bytes == 1) { bytes = bytes + " byte"; }
else { bytes = "0 bytes"; }
return bytes;
}
这是正确的做法吗?有没有更简单的方法?
当与字节相关时,有两种真实的方法来表示大小,它们是SI单位(10^3)或IEC单位(2^10)。也有JEDEC,但他们的方法是模糊的和令人困惑的。我注意到其他示例有错误,例如使用KB而不是KB来表示千字节,因此我决定编写一个函数,使用当前接受的度量单位的范围来解决这些情况。
在结尾有一个格式化的地方,这将使数字看起来更好一点(至少在我看来),如果它不适合你的目的,请随意删除这个格式。
享受。
// pBytes: the size in bytes to be converted.
// pUnits: 'si'|'iec' si units means the order of magnitude is 10^3, iec uses 2^10
function prettyNumber(pBytes, pUnits) {
// Handle some special cases
if(pBytes == 0) return '0 Bytes';
if(pBytes == 1) return '1 Byte';
if(pBytes == -1) return '-1 Byte';
var bytes = Math.abs(pBytes)
if(pUnits && pUnits.toLowerCase() && pUnits.toLowerCase() == 'si') {
// SI units use the Metric representation based on 10^3 as a order of magnitude
var orderOfMagnitude = Math.pow(10, 3);
var abbreviations = ['Bytes', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
} else {
// IEC units use 2^10 as an order of magnitude
var orderOfMagnitude = Math.pow(2, 10);
var abbreviations = ['Bytes', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB'];
}
var i = Math.floor(Math.log(bytes) / Math.log(orderOfMagnitude));
var result = (bytes / Math.pow(orderOfMagnitude, i));
// This will get the sign right
if(pBytes < 0) {
result *= -1;
}
// This bit here is purely for show. it drops the percision on numbers greater than 100 before the units.
// it also always shows the full number of bytes if bytes is the unit.
if(result >= 99.995 || i==0) {
return result.toFixed(0) + ' ' + abbreviations[i];
} else {
return result.toFixed(2) + ' ' + abbreviations[i];
}
}
如果表示的单位小于10 KB或更大,则此解决方案包括一个小数点和一个十分位数字
const units = ['bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
function niceBytes(x){
let l = 0, n = parseInt(x, 10) || 0;
while(n >= 1024 && ++l){
n = n/1024;
}
return(n.toFixed(n < 10 && l > 0 ? 1 : 0) + ' ' + units[l]);
}
结果:
niceBytes(7) // 7 bytes
niceBytes(435) // 435 bytes
niceBytes(3398) // 3.3 KB
niceBytes(490398) // 479 KB
niceBytes(6544528) // 6.2 MB
niceBytes(23483023) // 22 MB
niceBytes(3984578493) // 3.7 GB
niceBytes(30498505889) // 28 GB
niceBytes(9485039485039445) // 8.4 PB
这是一个坚实的有效的方法来转换字节。你唯一需要做的就是安装mathjs库进行精确的计算。复制粘贴即可。
import { multiply, divide, round } from "mathjs";
class Size {
constructor(value, unit) {
this.value = value;
this.unit = unit.toUpperCase();
}
}
async function byteToSize(bytes) {
const B = 1;
const KB = multiply(B, 1024);
const MB = multiply(KB, 1024);
const GB = multiply(MB, 1024);
const TB = multiply(GB, 1024);
const PB = multiply(TB, 1024);
if (bytes <= KB) {
// @returns BYTE
const result = round(divide(bytes, B));
const unit = `B`;
return new Size(result, unit);
}
if (bytes <= MB) {
// @returns KILOBYTE
const result = round(divide(bytes, KB));
const unit = `KB`;
return new Size(result, unit);
}
if (bytes <= GB) {
// @returns MEGABYTE
const result = round(divide(bytes, MB));
const unit = `MB`;
return new Size(result, unit);
}
if (bytes <= TB) {
// @returns GIGABYTE
const result = round(divide(bytes, GB));
const unit = `GB`;
return new Size(result, unit);
}
if (bytes <= PB) {
// @returns TERABYTE
const result = divide(bytes, TB).toFixed(2);
const unit = `TB`;
return new Size(result, unit);
}
if (bytes >= PB) {
// @returns PETABYTE
const result = divide(bytes, PB).toFixed(2);
const unit = `PB`;
return new Size(result, unit);
}
}
我只是想分享我的想法。我遇到了这个问题,所以我的解决方案是这样的。这将把低单位转换为高单位,反之亦然,只需提供参数toUnit和fromUnit
export function fileSizeConverter(size: number, fromUnit: string, toUnit: string ): number | string {
const units: string[] = ['B', 'KB', 'MB', 'GB', 'TB'];
const from = units.indexOf(fromUnit.toUpperCase());
const to = units.indexOf(toUnit.toUpperCase());
const BASE_SIZE = 1024;
let result: number | string = 0;
if (from < 0 || to < 0 ) { return result = 'Error: Incorrect units'; }
result = from < to ? size / (BASE_SIZE ** to) : size * (BASE_SIZE ** from);
return result.toFixed(2);
}
我从这里得到了灵感