例如数组长度为5，随机数区间2-32

function test(min,max,len,arr = []){
    let num = Math.floor(min+Math.random()*(max-min));   
    if(arr.indexOf(num) === -1){
        arr.push(num)
    }
    if(arr.length<len){
        return test(min,max,len,arr)
    }else{
        return arr
    }
}
console.log(test(2,32,5));

优化

function test(min,max,len,arr = []){
    let num = Math.floor(min+Math.random()*(max-min));   
    arr.includes(num) ? arr : arr.push(num);
    return arr.length === len ? arr : test(min,max,len,arr);
}
console.log(test(2,32,5));