数组排序

let shw2 = [1,3,5,2,1]

                shw2.forEach((item, index) => {

                    var min = item;

                    var temp;

                    var minIndex = index;

                    for (var j = index + 1; j < shw2.length; j++) {

                        if (shw2[j] < min) {

                            min = shw2[j];

                            minIndex = j;

                        }

                    }

                    temp = shw2[index];

                    shw2[index] = min;

                    shw2[minIndex] = temp;

                })

console.log(shw2)//结果为:[1, 1, 2, 3, 5]