筛选前十按a-z顺序排

需求：

　　从arr数组中筛选出num最多的前十个，若是最后几个num的值一样，则最后几个按字母a-z的顺序排序，最后取出num最大的前十个；

var arr = [{"id":"f820be55a8d8c27fe7980a8b41136049","name":"曹祎遐","num":28},{"id":"71d9846327605ed2fe9e442e4cea6eac","name":"李湛","num":8},{"id":"f5b302d4db933f78e96e37c6cc3139b3","name":"刘亮","num":4},{"id":"51d7ef8f45f82f43a18980b30a94737e","name":"李伟","num":4},{"id":"2093b01d717ffe3128999f41ebcd2164","name":"郁鸿胜","num":3},{"id":"bc0afa6ce17851d31aedc1d8f9bfa917","name":"俞晓晶","num":2},{"id":"6c9294d61e7e71abcb1ce4b36614c1f9","name":"徐赟","num":2},{"id":"ce14cdd8ea8f7945f7e13e005f654d62","name":"李小年","num":1},{"id":"1e543e4e1e7c3ccbf759b050af428da9","name":"万勇","num":1},{"id":"4d14f8dd74bafeabb48322f10184d231","name":"杨咸月","num":1},{"id":"deb43756040116ce7077f5ad291cec0c","name":"孙福庆","num":1},{"id":"f2ef2572a283f814856959d5fa5447b8","name":"郑琦","num":1},{"id":"0e0b257d6a78fe3968ece09740a0af7a","name":"陈建勋","num":1},{"id":"63e91b532a24e987ef51c054f8377572","name":"顾书桂","num":1},{"id":"fa3e4703b1e6f99bc076ff84433b25a3","name":"郑世卿","num":1},{"id":"a6cfb26c3f7d8a35e5cd9b335aa7ee69","name":"顾丽英","num":1}]

let newArr = arr.sort((a,b)=>{
    return (b.num - a.num) && (a.name.localeCompare(b.name,"zh-CN"))
})

console.log(newArr)

let topTen = newArr.slice(0,10)
console.log(topTen[9])
let newTop = []
topTen.forEach(item=>{
    if(item.num!=topTen[9].num){
        newTop.push(item)
    }
})
let len = newTop.length
let lastNums = []
arr.forEach(item=>{
    if(item.num == topTen[9].num){
        lastNums.push(item)
    }
})
let orderByName = lastNums.sort((a,b)=>{
    return a.name.localeCompare(b.name,"zh-CN")
})

let concatArr = newTop.concat(orderByName.slice(0,10-len))