js在取值范围内获取数量固定且不重复的随机数,形成一个数组

//a为最小数,b为最大数,c为数组长度
        function autoArr(a, b, c) {
            let arr1 = new Array();
            for (let i = a; i < b + 1; i++) {
                arr1.push(i);
            }
            console.log(arr1);
            for (let i = 0; i < b - c + 1; i++) {
                let NUM = parseInt(Math.random() * arr1.length);
                let newArr = arr1.slice(NUM, NUM + 1);
                arr1.splice(NUM, 1);
            }
        }