数据类型转换

string - int
var day = parseInt(120900 / (1000 * 60));
int- string
var days = day.toString();

https://blog.csdn.net/shanshan_1117/article/details/89371296

二。数据使用

https://www.jianshu.com/p/185efaea230c

数组复制

    let arr = [];
    arr[0] = "a";
    arr[3] = "b";

    this.data.listLoad = arr.slice();

数组遍历

    let arr = [];
    arr[0] = "a";
    arr[3] = "b";
    arr[10] = "c";
    arr[6] = "Hello world";
    arr.forEach((data, index, array) => {
      console.log(data, index);
    });

数组删除元素

    let arr = [];
    arr[0] = "a";
    arr[1] = "b";
    arr[2] = "c";
    arr[3] = "Hello world";
    arr.splice(1, 2)//删除下标为1的2个数
    console.log('-=-=-=-=-=-=='+arr);