js 数组如何重新分组归类？

Question

let a = [
  {name:'深圳-宝安'},
  {name:'广州-南沙'},
  {name:'深圳-福田'},
  {name:'广州-番禺'},
]

需要得到：

let b = [
  {
     Province:'广州',
     childList: [
       {city: '南沙'},
       {city: '番禺'}
     ]
  },
  {
     Province:'深圳',
     childList: [
       {city: '宝安'},
       {city: '福田'}
     ]
  }
]

Answer 1

let b = a.reduce((res, item) => {
    let [province, city] = item.name.split('-')
    let parent = res.find(i => i.Province === province)
    if(parent){
        parent.childList.push({city})
    }else{
        res.push({Province: province, childList: [{city}]})
    }
    return res
}, [])

Answer 2

tmp = {};
b = [];

for (let item of a) {
    const [cityName, areaName] = item.name.split('-');
    if (tmp[cityName] === undefined) {
        tmp[cityName] = b.length;
        b.push({ Province: cityName, childList: [ { city: areaName } ] });
    } else {
        const cur = b[tmp[cityName]];
        b[tmp[cityName]] = { ...cur, childList: [ ...cur.childList, { city: areaName } ] };
    }
}

Answer 3

const b = Object
    .entries(
        a.map(({ name }) => name.split("-"))
            .reduce((group, [province, city]) => {
                (group[province] ??= []).push({ city });
                return group;
            }, {})
    )
    .map(([Province, childList]) => ({ Province, childList }));

console.dir(b, { depth: null });

---

我看你关于集合数据处理的问题不少啊，来看看这两篇：

• JavaScript 数据处理 - 列表篇
• JavaScript 数据处理 - 映射表篇

Answer 4

let a = [
        {name: '深圳-宝安'},
        {name: '广州-南沙'},
        {name: '深圳-福田'},
        {name: '广州-番禺'},
    ]

    let b = a.map(it => {
        let splits = it.name.split("-");
        return {
            province: splits[0],
            city: splits[1],
        }
    })
    let c = b.reduce((acc, item) => {
        const finder = acc.find(subItem => subItem.province === item.province)
        if (!finder) {
            acc.push({
                province: item.province,
                childList: [item]
            })
        } else {
            finder.childList.push(item)
        }
        return acc;
    }, [])
    console.log(c)