在JavaScript中将大小(以字节为单位)转换为KB,MB,GB的正确方法

Question

我得到这个代码通过PHP来隐藏大小的字节数.

现在我想使用JavaScript 将这些大小转换为人类可读的大小.我试图将此代码转换为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;
}

这是正确的做法吗？有没有更简单的方法？

Answer 1

由此:( 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];
}

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

现在,修正版:( 通过Stackoverflow的社区,+由JSCompress缩小)

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];
}

用法:

function formatBytes(a,b){if(0==a)return"0 Bytes";var c=1024,d=b||2,e=["Bytes","KB","MB","GB","TB","PB","EB","ZB","YB"],f=Math.floor(Math.log(a)/Math.log(c));return parseFloat((a/Math.pow(c,f)).toFixed(d))+" "+e[f]}

演示/来源:

// formatBytes(bytes,decimals)

formatBytes(1024);       // 1 KB
formatBytes('1024');     // 1 KB
formatBytes(1234);       // 1.21 KB
formatBytes(1234, 3);    // 1.205 KB

function formatBytes(bytes,decimals) {
   if(bytes == 0) return '0 Bytes';
   var k = 1024,
       dm = decimals <= 0 ? 0 : decimals || 2,
       sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'],
       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);

PS:更改k = 1000或sizes = ["..."]根据需要(位或字节)

Answer 2

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";
}

Answer 3

const units = ['bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];

function niceBytes(x){
  if(x === 1) return '1 byte';

  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]);
}

结果:

niceBytes(1)                   // 1 byte
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

Answer 4

您可以使用filesizejs库.

Answer 5

当与字节相关时,有两种实际方式来表示大小,它们是SI单位(10 ^ 3)或IEC单位(2 ^ 10).还有JEDEC,但他们的方法含糊不清,令人困惑.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范围来解决每个案例.

最后有一个格式化位会使数字看起来更好(至少在我看来)如果它不适合你的目的,可以随意删除该格式.

请享用.

// 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];
    }
}

Answer 6

这是一个班轮:

val => ['Bytes','Kb','Mb','Gb','Tb'][Math.floor(Math.log2(val)/10)]

甚至:

val => 'BKMGT'[~~(Math.log2(val)/10)]

Answer 7

将字节格式化为最逻辑大小（KB、MB 或 GB）的实用方法

Number.prototype.formatBytes = function() {
    var units = ['B', 'KB', 'MB', 'GB', 'TB'],
        bytes = this,
        i;
 
    for (i = 0; bytes >= 1024 && i < 4; i++) {
        bytes /= 1024;
    }
 
    return bytes.toFixed(2) + units[i];
}

let a = 235678; //bytes

console.log(a.formatBytes()); //result is 230.15KB

Answer 8

只需稍微修改 @zayarTun 答案的代码，以包含一个表示结果中小数位数的额外参数（另外，如果小数为零，则无需显示 15.00 KB 之类的结果，而是 15 KB 就足够了，这就是我包装的原因中的结果值parseFloat()）

  bytesForHuman(bytes, decimals = 2) {
    let units = ['B', 'KB', 'MB', 'GB', 'TB', 'PB']

    let i = 0
    
    for (i; bytes > 1024; i++) {
        bytes /= 1024;
    }

    return parseFloat(bytes.toFixed(decimals)) + ' ' + units[i]
  }

Answer 9

这对我有用。

bytesForHuman(bytes) {
    let units = ['B', 'KB', 'MB', 'GB', 'TB', 'PB']

    let i = 0
    
    for (i; bytes > 1024; i++) {
        bytes /= 1024;
    }

    return bytes.toFixed(1) + ' ' + units[i]
}

Answer 10

使用按位运算将是更好的解决方案.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 ;
}