hex16.js

hex16.js

// echo -en "\x01\x02\x03\x04\x05\x06hello world\x07\x08\x09\x10goodbye world\x11\x12\x13\x14\x15" > data

let fs = require('fs')
let file = process.argv.slice(2)[0]

function hexdump(file) {
  let buffer = fs.readFileSync(file)
  let lines = []

  for (let i = 0; i < buffer.length; i += 16) {
    let address = i.toString(16).padStart(8, '0')
    let block = buffer.slice(i, i + 16)
    let array16 = []

    for (let j = 0; j < block.length; j += 2) {
      if (j < block.length - 1) {
        array16.push((block[j] << 8) | (block[j + 1] << 0))
      }
    }

    let hexString = array16.map(value => value.toString(16).padStart(4, '0')).join(' ')
    lines.push(`${address}  ${hexString}`)
  }

  return lines.join('\n')
}

console.log(hexdump(file))

// 00000000  0102 0304 0506 6865 6c6c 6f20 776f 726c
// 00000010  6407 0809 1067 6f6f 6462 7965 2077 6f72
// 00000020  6c64 1112 1314