JS written test questions -- random numbers, array de duplication

Please complete it JavaScript Code , Implement a function , Requirements are as follows ：

1. According to the number range entered [start,end] And random numbers "n" Generate random number
2. The generated random number is stored in the array , Return the array
3. The returned array cannot have the same elements

			            const _getUniqueNums = (start,end,n) => {
			                //  The completion code 
			                let arr=[]
			                for(let i=0;i<n;i++){
			                    let b=Math.ceil(Math.random()*(end-(start)+start))
			                    arr[i]=b;
			                }
			                let set1=new Set(arr);
			                let arr1=Array.from(set1);
			                return arr1
			            }
						console.log(_getUniqueNums(2,10,4))

Add ： There are some knowledge points Math Of random Random , Array de duplication method .
summary ： random Random number method , Determine the range format ：Math.random()*(end-(start)+start)
Rounding can be used ceil or floor Method .
Array de duplication can be used Set Method , It also uses the non repetition of object key names to achieve, and so on