The problem
Need to display file sizes in a user-friendly format
The solution
function formatFileSize(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];
}
// Alternative: Binary (IEC) format
function formatFileSizeBinary(bytes, decimals = 2) {
if (bytes === 0) return '0 Bytes';
const k = 1024;
const dm = decimals < 0 ? 0 : decimals;
const sizes = ['Bytes', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB'];
const i = Math.floor(Math.log(bytes) / Math.log(k));
return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
}Parameters
bytesnumberFile size in bytes
decimalsnumberNumber of decimal places (default: 2)
Put it to work
console.log(formatFileSize(0)); // "0 Bytes"
console.log(formatFileSize(500)); // "500 Bytes"
console.log(formatFileSize(1024)); // "1 KB"
console.log(formatFileSize(1500000)); // "1.43 MB"
console.log(formatFileSize(1500000000)); // "1.4 GB"
console.log(formatFileSize(1500000000000)); // "1.36 TB"
console.log(formatFileSizeBinary(1024)); // "1 KiB"
console.log(formatFileSizeBinary(1048576)); // "1 MiB"