formatBytes - Format bytes as human-readable text.

formatBytes.js

/**
 * Format bytes as human-readable text.
 * @param {number} bytes Number of bytes.
 * @param {number} decimalPlaces Number of decimal places to display.
 * @param {number} baseQuantity Number of bytes in a kilobyte.
 * @param {string[]} sizes The unites to use for each power of the baseQuantity.
 * @return {string} Formatted byte size.
 */
export const formatBytes = (
  bytes,
  decimalPlaces = 1,
  baseQuantity = 1024,
  sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB', 'PB']
) => {
  if (bytes === 0) return 'n/a'
  const i = parseInt(Math.floor(Math.log(bytes) / Math.log(baseQuantity)), 10)
  if (i === 0) return `${bytes} ${sizes[i]}`
  return `${(bytes / baseQuantity ** i).toFixed(decimalPlaces)} ${sizes[i]}`
}

/**
 * Format bytes as human-readable text using SI (decimal) prefixes.
 * @param {number} bytes Number of bytes.
 * @param {number} decimalPlaces Number of decimal places to display.
 * @return {string} Formatted byte size.
 */
export const formatBytesSI = (bytes, decimalPlaces) =>
  formatBytes(bytes, decimalPlaces, 1000, [
    'Bytes',
    'kB',
    'MB',
    'GB',
    'TB',
    'PB',
  ])

/**
 * Format bytes as human-readable text using IEC (binary) prefixes.
 * @param {number} bytes Number of bytes.
 * @param {number} decimalPlaces Number of decimal places to display.
 * @return {string} Formatted byte size.
 */
export const formatBytesIEC = (bytes, decimalPlaces) =>
  formatBytes(bytes, decimalPlaces, 1024, [
    'Bytes',
    'KiB',
    'MiB',
    'GiB',
    'TiB',
    'PiB',
  ])