week4.js

/*
--- Day 4: High-Entropy Passphrases ---
A new system policy has been put in place that requires all accounts to use a
passphrase instead of simply a password. A passphrase consists of a series of
words (lowercase letters) separated by spaces.

To ensure security, a valid passphrase must contain no duplicate words.

For example:

aa bb cc dd ee is valid.
aa bb cc dd aa is not valid - the word aa appears more than once.
aa bb cc dd aaa is valid - aa and aaa count as different words.
The system's full passphrase list is available as your puzzle input.
How many passphrases are valid?
*/

const validPassphrases = (passphraseArray) => {
  let validCount = 0;

  passphraseArray.forEach(passphrase => {
    const singlePassphrase = passphrase.split(' '),
      passphraseSet = new Set(singlePassphrase);

    if (passphraseSet.size === singlePassphrase.length) {
      validCount++;
    };
  });

  return validCount;
};

module.exports.validPassphrases = validPassphrases;