binarify.js

#!/usr/bin/env node

/**

 ./binarify.js < SOME_FILE > OUT_FILE
 ./binarify.js -d < OUT_FILE
 
*/

const { Transform } = require("stream");
const partition = (r,j) => r.reduce((a,b,i,g) => !(i % j) ? a.concat([g.slice(i,i+j)]) : a, []);
const octet = bits => bits.reduce((o, bit, index) => o + bit * (1 << (7 - index)), 0);

const encode = new Transform({
  transform: function transformer(chunk, encoding, callback) {
    const binary = [...chunk].map(byte => byte.toString(2).padStart(8, "0")).join("");
    callback(false, binary);
  }
});

const decode = new Transform({
  transform: function transformer(chunk, encoding, callback) {
    const bits = [...chunk].map(c => String.fromCharCode(c)).map(Number);
    const bytes = partition(bits, 8).map(octet);
    callback(false, Buffer.from(bytes));
  }
});

const transform = process.argv[2] === "-d" ? decode : encode;
process.stdin.pipe(transform).pipe(process.stdout);