Misago/frontend/src/utils/file-size.js

export default function(bytes) {
  if (bytes > 1024 * 1024 * 1024) {
    return roundSize(bytes / (1024 * 1024 * 1024)) + ' GB';
  } else if (bytes > 1024 * 1024) {
    return roundSize(bytes / (1024 * 1024)) + ' MB';
  } else if (bytes > 1024) {
    return roundSize(bytes / 1024) + ' KB';
  } else {
    return roundSize(bytes) + ' B';
  }
}

export function roundSize(value) {
  return value.toFixed(1);
}