编辑代码

function quickSort(arr) {
    if(arr.length <= 1) return arr;
    const base = arr[0];
    let left = [], right = [];
    for(let i = 1, len = arr.length; i < len; i++) {
        const item = arr[i]
        if(item < base ) {
            left.push(item)
        } else {
            right.push(item)
        }
    }
    return [...quickSort(left), base, ...quickSort(right)]
}
const testArr = [1,5,7,8,9,6,4,5,6,3,2,7]
console.log(quickSort(testArr))