我使用这个函数将文件大小(以字节为单位)转换为人类可读的文件大小:
零二线函数 var i = -1; var byteUnits =[英国‘计划生育’‘兆’,‘和合’,‘PB’‘EB”、“ZB’,‘YB]; do { fileSizeInBytes /= 1024; 我+; while (fileSizeInBytes > 1024) 数学归来。max(fileSizeInBytes, 0.1)。toFixed(1) + byteUnits[i]; 的 控制台日志(getReadableFileSizeString (1551859712);//输出是“1.4 GB”
然而，这似乎不是百分之百准确的。例如:
getReadableFileSizeString(1551859712); // output is "1.4 GB"
不应该是“1.5 GB”吗?除以1024似乎失去了精度。是我完全误解了什么，还是有更好的办法?
当前回答
基于cocco的想法，这里有一个不太紧凑但希望更全面的示例。
<!DOCTYPE html>
<html>
<head>
<title>File info</title>
<script>
<!--
function fileSize(bytes) {
var exp = Math.log(bytes) / Math.log(1024) | 0;
var result = (bytes / Math.pow(1024, exp)).toFixed(2);
return result + ' ' + (exp == 0 ? 'bytes': 'KMGTPEZY'[exp - 1] + 'B');
}
function info(input) {
input.nextElementSibling.textContent = fileSize(input.files[0].size);
}
-->
</script>
</head>
<body>
<label for="upload-file"> File: </label>
<input id="upload-file" type="file" onchange="info(this)">
<div></div>
</body>
</html>
其他回答
这是我写的一个:
/** * Format bytes as human-readable text. * * @param bytes Number of bytes. * @param si True to use metric (SI) units, aka powers of 1000. False to use * binary (IEC), aka powers of 1024. * @param dp Number of decimal places to display. * * @return Formatted string. */ function humanFileSize(bytes, si=false, dp=1) { const thresh = si ? 1000 : 1024; if (Math.abs(bytes) < thresh) { return bytes + ' B'; } const units = si ? ['kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'] : ['KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB']; let u = -1; const r = 10**dp; do { bytes /= thresh; ++u; } while (Math.round(Math.abs(bytes) * r) / r >= thresh && u < units.length - 1); return bytes.toFixed(dp) + ' ' + units[u]; } console.log(humanFileSize(1551859712)) // 1.4 GiB console.log(humanFileSize(5000, true)) // 5.0 kB console.log(humanFileSize(5000, false)) // 4.9 KiB console.log(humanFileSize(-10000000000000000000000000000)) // -8271.8 YiB console.log(humanFileSize(999949, true)) // 999.9 kB console.log(humanFileSize(999950, true)) // 1.0 MB console.log(humanFileSize(999950, true, 2)) // 999.95 kB console.log(humanFileSize(999500, true, 0)) // 1 MB
这是我的-也适用于真正大的文件-_-
function formatFileSize(size)
{
var sizes = [' Bytes', ' KB', ' MB', ' GB', ' TB', ' PB', ' EB', ' ZB', ' YB'];
for (var i = 1; i < sizes.length; i++)
{
if (size < Math.pow(1024, i)) return (Math.round((size/Math.pow(1024, i-1))*100)/100) + sizes[i-1];
}
return size;
}
我的回答可能晚了，但我想它会帮助到某人。
度量前缀:
/**
* Format file size in metric prefix
* @param fileSize
* @returns {string}
*/
const formatFileSizeMetric = (fileSize) => {
let size = Math.abs(fileSize);
if (Number.isNaN(size)) {
return 'Invalid file size';
}
if (size === 0) {
return '0 bytes';
}
const units = ['bytes', 'kB', 'MB', 'GB', 'TB'];
let quotient = Math.floor(Math.log10(size) / 3);
quotient = quotient < units.length ? quotient : units.length - 1;
size /= (1000 ** quotient);
return `${+size.toFixed(2)} ${units[quotient]}`;
};
二进制前缀:
/**
* Format file size in binary prefix
* @param fileSize
* @returns {string}
*/
const formatFileSizeBinary = (fileSize) => {
let size = Math.abs(fileSize);
if (Number.isNaN(size)) {
return 'Invalid file size';
}
if (size === 0) {
return '0 bytes';
}
const units = ['bytes', 'kiB', 'MiB', 'GiB', 'TiB'];
let quotient = Math.floor(Math.log2(size) / 10);
quotient = quotient < units.length ? quotient : units.length - 1;
size /= (1024 ** quotient);
return `${+size.toFixed(2)} ${units[quotient]}`;
};
例子:
// Metrics prefix
formatFileSizeMetric(0) // 0 bytes
formatFileSizeMetric(-1) // 1 bytes
formatFileSizeMetric(100) // 100 bytes
formatFileSizeMetric(1000) // 1 kB
formatFileSizeMetric(10**5) // 10 kB
formatFileSizeMetric(10**6) // 1 MB
formatFileSizeMetric(10**9) // 1GB
formatFileSizeMetric(10**12) // 1 TB
formatFileSizeMetric(10**15) // 1000 TB
// Binary prefix
formatFileSizeBinary(0) // 0 bytes
formatFileSizeBinary(-1) // 1 bytes
formatFileSizeBinary(1024) // 1 kiB
formatFileSizeBinary(2048) // 2 kiB
formatFileSizeBinary(2**20) // 1 MiB
formatFileSizeBinary(2**30) // 1 GiB
formatFileSizeBinary(2**40) // 1 TiB
formatFileSizeBinary(2**50) // 1024 TiB
要在投票的解决方案中动态调整小数的数量，将bytes.toFixed(dp)转换为数字，然后再转换为字符串，就像这样:
return Number(bytes.toFixed(dp)).toString() + " " + units[u];
这将显示100 GiB而不是100.00 GiB。 在js中动态引用问题toFixed()
下面是一个将数字转换为符合新的国际标准的可读字符串的原型。
There are two ways to represent big numbers: You could either display them in multiples of 1000 = 10 3 (base 10) or 1024 = 2 10 (base 2). If you divide by 1000, you probably use the SI prefix names, if you divide by 1024, you probably use the IEC prefix names. The problem starts with dividing by 1024. Many applications use the SI prefix names for it and some use the IEC prefix names. The current situation is a mess. If you see SI prefix names you do not know whether the number is divided by 1000 or 1024
https://wiki.ubuntu.com/UnitsPolicy
http://en.wikipedia.org/wiki/Template:Quantities_of_bytes
Object.defineProperty(Number.prototype,'fileSize',{value:function(a,b,c,d){
return (a=a?[1e3,'k','B']:[1024,'K','iB'],b=Math,c=b.log,
d=c(this)/c(a[0])|0,this/b.pow(a[0],d)).toFixed(2)
+' '+(d?(a[1]+'MGTPEZY')[--d]+a[2]:'Bytes');
},writable:false,enumerable:false});
这个函数不包含循环，所以它可能比其他一些函数快。
用法:
IEC前缀
console.log((186457865).fileSize()); // default IEC (power 1024)
//177.82 MiB
//KiB,MiB,GiB,TiB,PiB,EiB,ZiB,YiB
如果prefix
console.log((186457865).fileSize(1)); //1,true for SI (power 1000)
//186.46 MB
//kB,MB,GB,TB,PB,EB,ZB,YB
我将IEC设置为默认值，因为我总是使用二进制模式来计算文件的大小…使用1024的幂
如果你只想在一个简短的线性函数中使用其中一个:
SI
function fileSizeSI(a,b,c,d,e){
return (b=Math,c=b.log,d=1e3,e=c(a)/c(d)|0,a/b.pow(d,e)).toFixed(2)
+' '+(e?'kMGTPEZY'[--e]+'B':'Bytes')
}
//kB,MB,GB,TB,PB,EB,ZB,YB
IEC
function fileSizeIEC(a,b,c,d,e){
return (b=Math,c=b.log,d=1024,e=c(a)/c(d)|0,a/b.pow(d,e)).toFixed(2)
+' '+(e?'KMGTPEZY'[--e]+'iB':'Bytes')
}
//KiB,MiB,GiB,TiB,PiB,EiB,ZiB,YiB
用法:
console.log(fileSizeIEC(7412834521));
如果你有关于函数的问题尽管问
