JS 将数字字符串数组转为 数字数组 （互换），js获取数组对象中 某一个key的值，js判断一个数组是否包含另一个数组（一维数组）

var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];
arr.map(String);  //结果： ['1', '2', '3', '4', '5', '6', '7', '8', '9']


var a = ['1', '2', '3', '4', '5', '6', '7', '8', '9']
a.map(Number);  //结果：[1, 2, 3, 4, 5, 6, 7, 8, 9]

    let arr= [
        {age:13,name:"a"},
        {age:14,name:""},
        {age:15,name:"c"},
        {age:16,name:"d"},
        {age:16,name:"e"},
    ]
    let nameArr = arr.map(item => item.name);
    console.log(nameArr);//["a", "", "c", "d", "e"]

    let a= [1,2,3,4];
    let b = [1,2,3]
    
    let result = b.every(item => (a.includes(item)));//b的所有值 是否包含于a
    console.log(result);//true
    let result2 = a.every(item => (b.includes(item)));//a的所有值 是否包含于b
    console.log(result2);//false