Solve http://www.playtypeshift.com like a pro

01_typeshift.js

const fs = require("fs");

const cartesian = (...a) => a.reduce((a, b) => a.flatMap(d => b.map(e => [d, e].flat())));
const intersection = (a, b) => new Set([...a].filter((x) => b.has(x)));

const letters = [
  ["n", "h", "i", "m", "w"],
  ["a", "h", "y", "i", "m"],
  ["c", "b", "x", "o", "l"],
  ["k", "o", "i", "u"],
  ["e", "s", "n"],
  ["g", "y", "h", "s", "d"],
];

function dictionary() {
  const str = fs.readFileSync("/usr/share/dict/words").toString();
  const words = str.split("\n").filter(Boolean);
  return new Set(words);
}

function trials(letters) {
  const words = [...cartesian(...letters)].map((x) => x.join(""));
  return new Set(words);
}

function main() {
  try {

    console.log(intersection(dictionary(), trials(letters)));

  } catch (e) {
    console.error(e);
    process.exit(1);
  }
}

main();

02_output

Set(9) {
  'hacked',
  'hickey',
  'macies',
  'nibong',
  'nickey',
  'waling',
  'waxing',
  'whoosh',
  'wicked'
}