修改state中数组对象某一个字段(state中某个属性为对象或数组时，需要修改该对象中的某一个属性)

this.state = {
    listData: [
        {name: "张三", age: "20"},
        {name: "李四", age: "21"},
    ],
    obj: {
        name: "王五",
        age: "22",
    }
}

change = (index) => {
    const listData = [...this.state.listData];   //复制数组--浅拷贝
    const obj = Object.assign({}, this.state.obj, { age: "21" });

    this.setState({
        listData: listData.map((item, idx) => idx === index ? {...item, name:  "赵六"} : item),
        obj: obj,                         
    })
}