code: function compare(hashstr, password, salt, iterations = 1024, keylen = 32, digest = 'sha256', encoding = 'hex') {
    return hash(password, salt, iterations, keylen, digest, encoding).then((data) => {
      return hashstr === data;
    });
  }
docs: Compare hash and  password + salt.
  
  @method
  @param {String} hashstr
  @param {String} password
  @param {string} salt
  @param {Number} [iterations] 1024
  @param {Number} [keylen] 32
  @param {String} [digest] sha256
  @param {String} [encoding] hex
  @return {Promise}