js reduce做数组的统计

1 let obj = {1:2}
2 let oop = {‘1‘:2}
3 console.log(typeof obj[1],typeof oop[‘1‘])//number 值都是2

function more(arr) {
    let num = null;
    let count = 1;
    //console.log(Math.min.apply(null,arr))
    let initNum = Math.min.apply(null,arr)
    arr.reduce((pre,cur)=>{
        console.log(pre,cur)
        if(pre[cur]){
            console.log(‘存在‘)
            pre[cur]=++pre[cur]
        }else{
            console.log(‘不存在‘)
            count=1
            pre[cur]=count
        }
        console.log(pre,cur)
        console.log(‘---------------------------------‘)
        return pre;
    },{})

}

let arrs = [1,2,1,3,2,3,3,4,4,4];
more(arrs)