whole_func_string: function del(key, cb) {
    if (!syncConfig.useCache || !redisClient) {
      return cb && cb();
    }
    return redisClient.del(key, cb);
  }
func_code_string: function del(key, cb) {
    if (!syncConfig.useCache || !redisClient) {
      return cb && cb();
    }
    return redisClient.del(key, cb);
  }
func_documentation_string: Delete data from cache
  @param {String} key
  @param {Function} cb