数组排序方法给不一样，我这就讲解一下最简单使用的排序。sort、冒泡排序、reverse倒序

• sort

    let arr = [2, 34, 1, 4, 6, 8, 9, 7, 9, 1, 4, 5, 293, 83] 
    arr.sort((a, b) => {
      //b - a：从大到小；a - b：从小到大
      return a - b
    })
    console.log(arr); // [1, 1, 2, 4, 4, 5, 6, 7, 8, 9, 9, 34, 83, 293]

• 冒泡排序

    let arr = [2, 34, 1, 4, 6, 8, 9, 7, 9, 1, 4, 5, 293, 83] 
    for (let index = 0; index < arr.length; index++) {
      for (let num = 0; num < arr.length; num++) {
        const numValue = arr[num];
        // <：从大到小；>：从小到大
        if (numValue < arr[num + 1]) {
          //调换数组里面值的位置
          arr[num] = arr[num + 1]
          arr[num + 1] = numValue
        }
      }
    }
    console.log(arr); // [293, 83, 34, 9, 9, 8, 7, 6, 5, 4, 4, 2, 1, 1]

• reverse倒序

    let arr = [2, 34, 1, 4, 6, 8, 9, 7, 9, 1, 4, 5, 293, 83] 
    arr.reverse()
    console.log(arr); // [83, 293, 5, 4, 1, 9, 7, 9, 8, 6, 4, 1, 34, 2]