问题
I got this code to covert size in bytes via PHP.
Now I want to convert those sizes to human readable sizes using JavaScript. I tried to convert this code to JavaScript, which looks like this:
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?
回答1:
From this: (source)
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. Aliceljm does not active her copied code anymore
Now, Fixed version unminified, and ES6'ed: (by community)
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)
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]}
Usage :
// formatBytes(bytes,decimals)
formatBytes(1024); // 1 KB
formatBytes('1024'); // 1 KB
formatBytes(1234); // 1.21 KB
formatBytes(1234, 3); // 1.205 KB
Demo / source :
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);<input type="text" value="1000">
<p></p>PS : Change k = 1000 or sizes = ["..."] as you want (bits or bytes)
回答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";
}
回答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]);
}
Results:
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
回答4:
You can use the filesizejs library.
回答5:
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.
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.
Enjoy.
// 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6:
Here's a one liner:
val => ['Bytes','Kb','Mb','Gb','Tb'][Math.floor(Math.log2(val)/10)]
Or even:
val => 'BKMGT'[~~(Math.log2(val)/10)]
回答7:
Using bitwise operation would be a better solution. Try this
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8:
According to Aliceljm's answer, I removed 0 after decimal:
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9:
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 0.98kb but being read as 1.02mb. Here's the updated code I'm now using.
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
// In this case `file.size` equals `26060275`
formatBytes(file.size);
// returns `{ size: 24.85, type: "mb" }`
Granted, Windows reads the file as being 24.8mb but I'm fine with the extra precision.
回答10:
function bytesToSize(bytes) {
var sizes = ['B', 'K', 'M', 'G', 'T', 'P'];
for (var i = 0; i < sizes.length; i++) {
if (bytes <= 1024) {
return bytes + ' ' + sizes[i];
} else {
bytes = parseFloat(bytes / 1024).toFixed(2)
}
}
return bytes + ' P';
}
console.log(bytesToSize(234));
console.log(bytesToSize(2043));
console.log(bytesToSize(20433242));
console.log(bytesToSize(2043324243));
console.log(bytesToSize(2043324268233));
console.log(bytesToSize(2043324268233343));回答11:
I am updating @Aliceljm answer here. Since the decimal place matters for 1,2 digit numbers, I am round off the first decimal place and keep the first decimal place. For 3 digit number, I am round off the units place and ignoring the all decimal places.
getMultiplers : function(bytes){
var unit = 1000 ;
if (bytes < unit) return bytes ;
var exp = Math.floor(Math.log(bytes) / Math.log(unit));
var pre = "kMGTPE".charAt(exp-1);
var result = bytes / Math.pow(unit, exp);
if(result/100 < 1)
return (Math.round( result * 10 ) / 10) +pre;
else
return Math.round(result) + pre;
}
回答12:
This solution builds upon previous solutions, but takes into account both metric and binary units:
function formatBytes(bytes, decimals, binaryUnits) {
if(bytes == 0) {
return '0 Bytes';
}
var unitMultiple = (binaryUnits) ? 1024 : 1000;
var unitNames = (unitMultiple === 1024) ? // 1000 bytes in 1 Kilobyte (KB) or 1024 bytes for the binary version (KiB)
['Bytes', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB']:
['Bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
var unitChanges = Math.floor(Math.log(bytes) / Math.log(unitMultiple));
return parseFloat((bytes / Math.pow(unitMultiple, unitChanges)).toFixed(decimals || 0)) + ' ' + unitNames[unitChanges];
}
Examples:
formatBytes(293489203947847, 1); // 293.5 TB
formatBytes(1234, 0); // 1 KB
formatBytes(4534634523453678343456, 2); // 4.53 ZB
formatBytes(4534634523453678343456, 2, true)); // 3.84 ZiB
formatBytes(4566744, 1); // 4.6 MB
formatBytes(534, 0); // 534 Bytes
formatBytes(273403407, 0); // 273 MB
回答13:
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]}`;
}回答14:
This is how a byte should be shown to a human:
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));
回答15:
Try this simple workaround.
var files = $("#file").get(0).files;
var size = files[0].size;
if (size >= 5000000) {
alert("File size is greater than or equal to 5 MB");
}
来源：https://stackoverflow.com/questions/15900485/correct-way-to-convert-size-in-bytes-to-kb-mb-gb-in-javascript