Hexdump in TypeScript

hexdump.ts

import type { Buffer } from "node:buffer";
import { open } from "node:fs/promises";
import { argv, stdin, stdout } from "node:process";

function printChars(chars: number[]) {
  stdout.write(" |");
  chars
    .map((c) => (c > 32 && c < 127 ? c : 46))
    .map((c) => stdout.write(String.fromCodePoint(c)));
  stdout.write("|\n");
}

function processStreamInput(chunk: Buffer) {
  let memoryAdress = 0x0;
  let codePoints = [];
  for (let i = 0; i < chunk.length; i++) {
    if (memoryAdress % 0x10 === 0x0) {
      stdout.write(memoryAdress.toString(16).padStart(8, "0"));
      stdout.write("  ");
    }
    const codePoint = Math.abs(chunk.readIntLE(i, 1));
    codePoints[memoryAdress % 0x10] = codePoint;
    stdout.write(codePoint.toString(16).padStart(2, "0"));
    stdout.write(" ");
    memoryAdress++;
    if (memoryAdress % 0x8 === 0x0) {
      stdout.write(" ");
    }
    if (memoryAdress % 0x10 === 0x0) {
      printChars(codePoints);
      codePoints = [];
    }
  }
  const quantityRemainingBytes = 3 * (0x10 - (memoryAdress % 0x10));
  stdout.write(
    " ".repeat(quantityRemainingBytes + (quantityRemainingBytes < 0x8 ? 1 : 2))
  );
  printChars(codePoints);
}

if (argv.length > 2) {
  const fd = await open(argv[2] as string);
  for await (const chunk of fd.createReadStream()) {
    processStreamInput(chunk);
  }
} else {
  for await (const chunk of stdin) {
    processStreamInput(chunk);
  }
}