_normalizeSinger 返回的是underfined

来源：5-4 listview 基础组件的开发和应用-滚动列表实现

慕前端9142252

2020-11-26

老师您好同样的代码为啥我的代码返回的就是underfined

   _getSingerList(){
       getSingerList().then(res=>{
           this.singers=this._normalizeSinger(res.data.list);
           console.log(this.singers)//这里返回的是underfined
       })
    },
    _normalizeSinger(list){
       const map = {
           hot:{
               title:HOT_NAME,
               item:[],
           }
       };
       list.forEach((item,index) => {
           if(index<HOT_SINGER_LENGTH){
               map.hot.item.push(new Singer({
                   id:item.Fsinger_mid,
                   name:item.Fsinger_name
               }))
           }
           const key =item.Findex;
           if(!map[key]){
               map[key]={
                   title:key,
                   item:[]
               }
           }
             map[key].item.push(new Singer({
                   id:item.Fsinger_mid,
                   name:item.Fsinger_name,
               }));
               let hot= []
               let ret = []
             for(let key in map){
                 if(map[key].title.match(/[a-zA-Z]/)){
                    ret.push(map[key])
                 }else if(map[key].title===HOT_NAME){
                     hot.push(map[key])
                 }
             };
             ret.sort((a,b)=>{
                 return a.title.charCodeAt(0)-b.title.charCodeAt(0);
             })
             return hot.concat(ret);
       });
    }

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2回答

我_PT

2020-12-02

这是我用ES6的map去整理的, 可以参考下

/**
 * 整理歌手列表数据
 */
normalizeSinger(singerList) {
  let map = new Map();
  let hotSingerArr = [];
  singerList.forEach((item, index) => {
      let singer = new Singer(item.Fsinger_mid, item.Fsinger_name);
      if (index < HOT_COUNT) {
        hotSingerArr.push(singer);
      }
      let singerIndex = item.Findex.toUpperCase();
      if (!map.has(singerIndex)) {
        let validSingerIndex = singerIndex.match(/[a-zA-Z]/);
        if (!validSingerIndex) return;
        map.set(singerIndex, []);
      }
      let groupContainer = map.get(singerIndex);
      groupContainer.push(singer);
    }
  );
  let mapArr = Array.from(map);
  mapArr.sort((before, after) => {
    let previousKeyCode = before[0].charCodeAt(0);
    let nextKeyCode = after[0].charCodeAt(0);
    return previousKeyCode - nextKeyCode;
  });
  mapArr.unshift([HOT_NAME, hotSingerArr]);
  return mapArr;
}