tagInfo() {
                const allTags = this.pxer.resultSet.reduce((result, works) => result.concat(works.tagList), []);
                const countMap = {};
                const noRepeatTags = [];

                allTags.forEach(tag => {
                    if (!noRepeatTags.includes(tag)) {
                        noRepeatTags.push(tag);
                    }
                    countMap[tag] = countMap[tag] || 0;
                    countMap[tag]++;
                });

                noRepeatTags.sort((tag1, tag2) => countMap[tag2] - countMap[tag1]);

                return {
                    tags: noRepeatTags,
                    count: countMap,
                }
            }
@return {TagInfo}

@typedef TagInfo
@property {Array.<string>} tags - all tags without repeat
@property {Object.<string, number>} count - The times of tag included in works