一些js题

1.年会抽红包，100个人，每人1-10块，最后全体平均每人7块钱 （无小数）

        demo(len) {

            // 每人给1块

            let arr = new Array(len).fill(1)

            let money = 700 - len

            // 随机找人给1块

            while (money > 0) {

                let i = parseInt(Math.random() * 100)

                if (arr[i] < 10) {

                    arr[i]++

                    money--

                }

            }

            return arr

        },

 2.获取不重复的随机数

getNotRepeatArr(len,num){
    let arr = new Array()
    for(let i = 0;i<len;i++){
        arr[i] = i
    }
    arr.sort(()=>0.5-Math.random())
    return arr.slice(0,num)
}

 3.数组对象中根据指定key来分类

let arr = [
    {a:1,b:2,c:3,value:'???'},
    {a:1,b:2,c:3,value:'2'},
    {a:1,b:3,c:3,value:'3'},
    {a:1,b:3,c:3,value:'f'},
    {a:2,b:2,c:3,value:'ds'},
    {a:3,b:2,c:4,value:'3'},
    {a:2,b:2,c:3,value:'v'},
    {a:4,b:2,c:3,value:'v'},
    {a:5,b:2,c:3,value:'v'},
    {a:3,b:6,c:3,value:'v'},
]
// 返回大树组 根据a b c相同放在同个数组

demo(arr){
    let res = []
    let i = 0
    let obj = {}
    arr.forEach(item=>{
        const {a,b,c} = item
        let key = `${a}-${b}-${c}`
        console.log(key,obj[key],i)
        if(Number.isInteger(obj[key])){
             res[obj[key]].push(item)
        }else {
            obj[key] = i
            res[i] = [item]
            i = i+1
        }
    })
   return res.filter(item=>item.length>1)
}