Potluck Server seed chain generator

server.seeds.chain.js

const Bluebird = require('bluebird');

/**
 * Create a `sha256` hash of the seed.
 * @param {String} seed - Previous server `seed`
 * @returns {String} `sha256` hash of the `seed`
*/
function createHash(seed) {
  return crypto.createHash('sha256').update(seed).digest('hex');
}

/**
 * Create an iterable to create seeds
 * @param {Number} total - total number of iterations
 * @returns {Object} an iterable that iterates for `total` times.
*/
function createIterable(total) {
  const seedIterable = {};
  seedIterable[Symbol.iterator] = function *steps() {
    let count = 0;
    while (count <= total) {
      yield count === 0;
      count += 1;
    }
  };
  return seedIterable;
}

/**
 * Save the server seed in database
 * @param {String} seed -seed to save
 * @returns saved server seed.
*/
function saveSeed(seed) {
  // save the seed somewhere in database.
  return Bluebird.resolve(seed);
}

/**
 * Create the server seed chain
 * @param {String} initialServerSeed - the value of first seed. (this is kept secret)
 * @param {Number} totalSeeds - total number of seeds to create.
 * @returns `sha256` hash of the final seed
*/
function generateSeeds(initialServerSeed, totalSeeds) {
  const seedIterable = createIterable(totalSeeds);
  // Create seeds one by one
  return Bluebird.reduce(seedIterable, (seed) => {
    const seedHash = createHash(seed);
    return saveSeed(seedHash);
  }, initialServerSeed);
}

if (require.main === module) {
  generateSeeds('secret initial seed ;-)', 1e7).then((finalSeed) => {
    const finalSeedHash = createHash(finalSeed);
    console.log(finalSeedHash); // Publish the final seed hash on forum before starting the game.
  }).catch((error) => console.error(error));
}

How it works??

Explain how it works

As in the end, it is now
).catch((error) => console.error(error))