平时小记

1、数组去重

let arr = [1,3,1,2,3,2,5,6,2,2,23,2,1,3]
let brr= Object.values(arr.reduce((cur,next)=>{
    console.log(cur)
    if(!cur[next]){
        cur[next] = next
    }
    return cur
},{}))
或者 
arr = [...new Set(arr)]
2、计算数组中每个元素出现的次数
let arr = [1,3,1,2,3,2,5,6,2,2,23,2,1,3]
let obj = arr.reduce((cur,next)=>{
    console.log(cur)
    if(!cur[next]){
        cur[next] = 1
    }else {
        cur[next] = cur[next]+1
    }
    return cur
},{})