js对json数组常用操作方法(增、删、改、查)

json数组

let persons = [
    {id:1,name: "Alex", age: 18},
    {id:2,name: "Teamo", age: 15},
    {id:3,name: "Lily", age: 16},
    {id:4,name: "Lucy", age: 16},
    {id:5,name: "Tom", age: 19}
]

新增一个对象

let alice = {name: ''Alice", age: 18};
persons.push(alice);

删除其中一个对象

//删除 name 等于 Alex的对象，利用splice()方法

//1. 首先我们要得到这个对象
let alex = persons.filter((p) => {
    return p.name == "Alex";
});

//2. 其次得到这个对象在数组中对应的索引
let index = persons.indexOf(alex[0]);

//3. 如果存在则将其删除，index > -1 代表存在
index > -1 && persons.splice(index, 1);

console.log(persons);
//打印结果 [{name: "Teamo", age: 15}, {name: "Lily", age: 16}, {name: "Lucy", age: 16}, {name: "Tom", age: 19}]

修改其中一个对象的属性值

//将 name 等于 Teamo的 age 修改为 20

//1. 得到 timo 对象
let teamo= persons.filter((p) => {
    return p.name == "Teamo";
});

//2. 修改age
teamo[0].age = 20;

查询筛选 filter

根据对象属性值得到相应对象

let twins = persons.filter((p) => {
    return p.age == 16;
});
console.log(twins); //打印结果 [{name: "Lily", age: 16},{name: "Lucy", age: 16}]