接口{
    data.map(school=>{
        接口(school.id){
            childrenData.map(student){
                
            }
        }
    })
}

正常来讲是这样的结构，第一次请求接口获取数据列表，通过遍历获取每一条数据的ID，再通过ID获取详细的信息，也就是接口数据循环、再嵌套接口、再循环数据。

循环后接口请求异步执行，显示不出子数据。

测试数据结构：

data:[
    {id:1, name:'A学校'},
    {id:2, name:'B学校'},
    {id:3, name:'C学校'},
],

//通过上面的id获取到的一条数据
childrenData:[
    {id:1, name:'张三', sex:'male', age:18},
    {id:2, name:'李四', sex:'female', age:18},
    {id:3, name:'王五', sex:'male', age:18},
]

 最终数据：

data:[
    {
        name:'A学校',
        children:[
            {id:1, name:'张三', sex:'male', age:18},
            {id:2, name:'李四', sex:'female', age:18},
            {id:3, name:'王五', sex:'male', age:18},
        ]
    },
    {
        name:'B学校',
        children:[
            {id:1, name:'赵刘', sex:'male', age:18},
            {id:2, name:'李四', sex:'female', age:18},
            {id:3, name:'王五', sex:'male', age:18},
        ]
    },
    {
        name:'C学校',
        children:[
            {id:1, name:'赵六', sex:'male', age:18},
            {id:2, name:'李四', sex:'female', age:18},
            {id:3, name:'王五', sex:'male', age:18},
        ]
    },
]

假设axios已封装，通过Promise链式调用，Promise.all在循环结束后再return，在里面new一个Promise，处理想要的数据，resolve一条数据，Promise.all后会自动变成数组。

其中async和await的作用，等待接口请求结束再resolve数据，同步执行

new Promise((resolve,reject)=>{
    return new Promise((resolve, reject)=>{
        getSchools().then(res=>{
            resolve(res.data)
        })
    }).then(schools=>{
        return Promise.all(schools.map(school=>{
            return new Promise(async (resolve,reject)=>{
                let schoolItem = {
                    name: school.name
                }
                await getStudents(school.id).then(students=>{
                    schoolItem.students = []
                    students.map(student=>{
                        const temp = {
                            name:student.name,
                            age:student.age,
                            sex:student.sex
                        }
                        schoolItem.students.push(temp)
                    })
                })
                resolve(schoolItem)
            })
        }))
    }).then(list=>{
        resolve(list)
    })
})