docs: function getKey(key, req) {
    var val = this._data[key];
  
    // got an expired key, delete it (active expiry)
    if(val && val.e && val.e <= Date.now()) {
      this.emit('expired', key);
      this.delKey(key, req);
      return undefined;
    }
  
    if(req) this.emit(val ? 'hit' : 'miss', key);
  
    if(typeof val === 'object') val.t = Date.now();
  
    return val ? val.v : undefined;
  }