在 JavaScript 中将字节大小转换为 KB、MB、GB 的正确方法
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Correct way to convert size in bytes to KB, MB, GB in JavaScript
提问by l2aelba
I got this codeto covert size in bytes via PHP.
我得到了这段代码，通过 PHP 以字节为单位隐藏大小。
Now I want to convert those sizes to human readablesizes using JavaScript. I tried to convert this code to JavaScript, which looks like this:
现在我想使用 JavaScript将这些大小转换为人类可读的大小。我尝试将此代码转换为 JavaScript，如下所示：
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;
}
Is this the correct way of doing this? Is there an easier way?
这是这样做的正确方法吗？有没有更简单的方法？
回答by Aliceljm
From this: (source)
从这里：（来源）
function bytesToSize(bytes) {
var sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB'];
if (bytes == 0) return '0 Byte';
var i = parseInt(Math.floor(Math.log(bytes) / Math.log(1024)));
return Math.round(bytes / Math.pow(1024, i), 2) + ' ' + sizes[i];
}
Note :This is original code, Please use fixed version below. Aliceljmdoes not active her copied code anymore
注意：这是原始代码，请使用下面的固定版本。Aliceljm不再激活她复制的代码
Now, Fixed version unminified, and ES6'ed:(by community)
现在，固定版本未缩小，ES6'ed：（由社区提供）
function formatBytes(bytes, decimals = 2) {
if (bytes === 0) return '0 Bytes';
const k = 1024;
const dm = decimals < 0 ? 0 : decimals;
const sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
const i = Math.floor(Math.log(bytes) / Math.log(k));
return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
}
Now, Fixed version :(by Stackoverflow's community, + Minified by JSCompress)
现在，固定版本：（由 Stackoverflow 社区提供，+ 由JSCompress 缩小）
function formatBytes(a,b=2){if(0===a)return"0 Bytes";const c=0>b?0:b,d=Math.floor(Math.log(a)/Math.log(1024));return parseFloat((a/Math.pow(1024,d)).toFixed(c))+" "+["Bytes","KB","MB","GB","TB","PB","EB","ZB","YB"][d]}
Usage :
用法 ：
// formatBytes(bytes,decimals)
formatBytes(1024); // 1 KB
formatBytes('1024'); // 1 KB
formatBytes(1234); // 1.21 KB
formatBytes(1234, 3); // 1.205 KB
Demo / source :
演示/源代码：
function formatBytes(bytes, decimals = 2) {
if (bytes === 0) return '0 Bytes';
const k = 1024;
const dm = decimals < 0 ? 0 : decimals;
const sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
const i = Math.floor(Math.log(bytes) / Math.log(k));
return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
}
// ** Demo code **
var p = document.querySelector('p'),
input = document.querySelector('input');
function setText(v){
p.innerHTML = formatBytes(v);
}
// bind 'input' event
input.addEventListener('input', function(){
setText( this.value )
})
// set initial text
setText(input.value);<input type="text" value="1000">
<p></p>PS : Change k = 1000or sizes = ["..."]as you want (bitsor bytes)
PS：更改k = 1000或sizes = ["..."]根据需要（位或字节）
回答by Jayram
function formatBytes(bytes) {
var marker = 1024; // Change to 1000 if required
var decimal = 3; // Change as required
var kiloBytes = marker; // One Kilobyte is 1024 bytes
var megaBytes = marker * marker; // One MB is 1024 KB
var gigaBytes = marker * marker * marker; // One GB is 1024 MB
var teraBytes = marker * marker * marker * marker; // One TB is 1024 GB
// return bytes if less than a KB
if(bytes < kiloBytes) return bytes + " Bytes";
// return KB if less than a MB
else if(bytes < megaBytes) return(bytes / kiloBytes).toFixed(decimal) + " KB";
// return MB if less than a GB
else if(bytes < gigaBytes) return(bytes / megaBytes).toFixed(decimal) + " MB";
// return GB if less than a TB
else return(bytes / gigaBytes).toFixed(decimal) + " GB";
}
回答by Faust
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;
}
//include a decimal point and a tenths-place digit if presenting
//less than ten of KB or greater units
return(n.toFixed(n < 10 && l > 0 ? 1 : 0) + ' ' + units[l]);
}
Results:
结果：
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
回答by maurocchi
You can use the filesizejslibrary.
您可以使用filesizejs库。
回答by Brennan T
There are 2 real ways to represent sizes when related to bytes, they are SI units (10^3) or IEC units (2^10). There is also JEDEC but their method is ambiguous and confusing. I noticed the other examples have errors such as using KB instead of kB to represent a kilobyte so I decided to write a function that will solve each of these cases using the range of currently accepted units of measure.
当与字节相关时，有两种实际的方式来表示大小，它们是 SI 单位 (10^3) 或 IEC 单位 (2^10)。还有 JEDEC，但他们的方法模棱两可且令人困惑。我注意到其他示例存在错误，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，该函数将使用当前接受的度量单位范围来解决每种情况。
There is a formatting bit at the end that will make the number look a bit better (at least to my eye) feel free to remove that formatting if it doesn't suit your purpose.
最后有一个格式位，可以使数字看起来更好（至少在我看来）如果它不适合您的目的，请随时删除该格式。
Enjoy.
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];
}
}
回答by iDaN5x
Here's a one liner:
这是一个单班轮：
val => ['Bytes','Kb','Mb','Gb','Tb'][Math.floor(Math.log2(val)/10)]
val => ['Bytes','Kb','Mb','Gb','Tb'][Math.floor(Math.log2(val)/10)]
Or even:
甚至：
val => 'BKMGT'[~~(Math.log2(val)/10)]
val => 'BKMGT'[~~(Math.log2(val)/10)]
回答by Buzz LIghtyear
Using bitwise operation would be a better solution. Try this
使用按位运算将是一个更好的解决方案。试试这个
function formatSizeUnits(bytes)
{
if ( ( bytes >> 30 ) & 0x3FF )
bytes = ( bytes >>> 30 ) + '.' + ( bytes & (3*0x3FF )) + 'GB' ;
else if ( ( bytes >> 20 ) & 0x3FF )
bytes = ( bytes >>> 20 ) + '.' + ( bytes & (2*0x3FF ) ) + 'MB' ;
else if ( ( bytes >> 10 ) & 0x3FF )
bytes = ( bytes >>> 10 ) + '.' + ( bytes & (0x3FF ) ) + 'KB' ;
else if ( ( bytes >> 1 ) & 0x3FF )
bytes = ( bytes >>> 1 ) + 'Bytes' ;
else
bytes = bytes + 'Byte' ;
return bytes ;
}
回答by abla
According to Aliceljm's answer, I removed 0 after decimal:
根据Aliceljm的回答，我删除了小数点后的 0：
function formatBytes(bytes, decimals) {
if(bytes== 0)
{
return "0 Byte";
}
var k = 1024; //Or 1 kilo = 1000
var sizes = ["Bytes", "KB", "MB", "GB", "TB", "PB"];
var i = Math.floor(Math.log(bytes) / Math.log(k));
return parseFloat((bytes / Math.pow(k, i)).toFixed(decimals)) + " " + sizes[i];
}
回答by theOneWhoKnocks
I originally used @Aliceljm's answer for a file upload project I was working on, but recently ran into an issue where a file was 0.98kbbut being read as 1.02mb. Here's the updated code I'm now using.
我最初使用@Aliceljm的答案来处理我正在处理的文件上传项目，但最近遇到了一个问题，文件0.98kb被读取为1.02mb. 这是我现在使用的更新代码。
function formatBytes(bytes){
var kb = 1024;
var ndx = Math.floor( Math.log(bytes) / Math.log(kb) );
var fileSizeTypes = ["bytes", "kb", "mb", "gb", "tb", "pb", "eb", "zb", "yb"];
return {
size: +(bytes / kb / kb).toFixed(2),
type: fileSizeTypes[ndx]
};
}
The above would then be called after a file was added like so
然后将在添加文件后调用上述内容，如下所示
// In this case `file.size` equals `26060275`
formatBytes(file.size);
// returns `{ size: 24.85, type: "mb" }`
Granted, Windows reads the file as being 24.8mbbut I'm fine with the extra precision.
当然，Windows 将文件读取为原样，24.8mb但我对额外的精度感到满意。
回答by Priladnykh Ivan
var SIZES = ['Bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
function formatBytes(bytes, decimals) {
for(var i = 0, r = bytes, b = 1024; r > b; i++) r /= b;
return `${parseFloat(r.toFixed(decimals))} ${SIZES[i]}`;
}