编辑代码

function errorCode(les,arr){
    if(les === 0){
        console.log("没有误码情况")
    }else if(les<0 || 0>255){
        console.log("误码总数目超出取值范围！")
    }else if(arr.length<0 || arr.length>1000){
        console.log("误码出现频率数组超出长度范围")
    }else{
        let times=[]
        for(let i = 0 ; i<arr.length; i++){
            let isExist = times.filter((n)=>{
                return n[0] === arr[i]
            }) 
            if(isExist.length === 0){
                let item = arr[i]
                let repeatNum = arr.filter((code)=>{
                    return code === item
                })
                if(repeatNum.length>0){
                    times.push([item,repeatNum.length])
                }
            }
        }
        times.sort(function(a,b){return b[1]-a[1]})

        let shortArr= [] 
        times.map((item)=>{
            if(item[1] === times[0][1]){
                let indexRange= []
                arr.map((code,i)=>{
                    if(code === item[0]){
                        indexRange.push(i) 
                    }
                })
               shortArr.push([item[0],[indexRange[0],indexRange[indexRange.length-1]]])
            }
        })
        shortArr.sort(function(a,b){
            let asum = a[1][1]-a[1][0] + 1
            let bsum = b[1][1]-b[1][0] + 1
            return asum - bsum
        })
        console.log(shortArr)
        console.log((shortArr[0][1][1]-shortArr[0][1][0]+1))

    }

}
// errorCode(5,[1,2,2,4,1])
errorCode(7,[1,2,2,4,2,1,1])