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?
这是一个字节应该如何显示给人类:
function bytesToHuman(bytes, decimals = 2) {
// https://en.wikipedia.org/wiki/Orders_of_magnitude_(data)
const units = ["bytes", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB"]; // etc
let i = 0;
let h = 0;
let c = 1 / 1023; // change it to 1024 and see the diff
for (; h < c && i < units.length; i++) {
if ((h = Math.pow(1024, i) / bytes) >= c) {
break;
}
}
// remove toFixed and let `locale` controls formatting
return (1 / h).toFixed(decimals).toLocaleString() + " " + units[i];
}
// test
for (let i = 0; i < 9; i++) {
let val = i * Math.pow(10, i);
console.log(val.toLocaleString() + " bytes is the same as " + bytesToHuman(val));
}
// let's fool around
console.log(bytesToHuman(1023));
console.log(bytesToHuman(1024));
console.log(bytesToHuman(1025));
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
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];
}
}
我有一个问题的元数据从服务器返回不同大小的单位。我使用了@Alicejim response，并试图让它更通用。在这里分享代码，也许会帮助到一些人。
enum SizeUnits {
Bytes = 'Bytes',
KB = 'KB',
MB = 'MB',
GB = 'GB',
TB = 'TB',
PB = 'PB',
EB = 'EB',
ZB = 'ZB',
YB = 'YB'
}
function convertSizeUnites(size: number, sourceSizeUnits: SizeUnits, targetSizeUnits: SizeUnits) {
const i = Object.keys(SizeUnits).indexOf(sourceSizeUnits);
const sizeInBytes = size * Math.pow(1024, i);
const j = Object.keys(SizeUnits).indexOf(targetSizeUnits);
return sizeInBytes / Math.pow(1024, j);
}
function formatSize(size: number, measureUnit: SizeUnits, decimals = 2) {
if (size === 0) return '0 Bytes';
const sizeInBytes = convertSizeUnites(size, measureUnit, SizeUnits.Bytes);
const dm = decimals < 0 ? 0 : decimals;
const i = Math.floor(Math.log(sizeInBytes) / Math.log(1024));
return parseFloat((sizeInBytes / Math.pow(1024, i)).toFixed(dm)) + ' ' +
Object.keys(SizeUnits)[i];
}
