javascript - 替换状态数组中的项目

Question

我已经研究了一段时间如何替换状态数组中已经存在的项目，但我找不到合适的解决方案
https://codesandbox.io/s/4xl24j7r69

import React from 'react';


class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      data: [
        {
          "userId": 1,
          "id": 1,
          "title": "One",
          "body": "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"
        },
        {
          "userId": 1,
          "id": 2,
          "title": "Two",
          "body": "est rerum tempore vitae\nsequi sint nihil reprehenderit dolor beatae ea dolores neque\nfugiat blanditiis voluptate porro vel nihil molestiae ut reiciendis\nqui aperiam non debitis possimus qui neque nisi nulla"
        },
      ]
    }
  }

  add = () => {
    this.setState(prevState => ({

      data: [...prevState.data,
      {
        "userId": 1,
        "id": 2,
        "title": "Two New",
        "body": "new data",
      }// this item already exist so I want to replace it to new data
      ]
    }))
  };
  render() {
    return (
      <div>
        {this.state.data.map((data) =>
          <ul key={data.id}>
            <li>{data.title}</li>
          </ul>
        )}
        <button onClick={this.add}>Replace</button>
      </div>
    );
  }
}
export default App;

我试过了，但是不行

 add = () => {
    this.setState(prevState => ({
      data: prevState.data.filter(item => this.state.data.indexOf(item.id) !== -1).slice(0, 5), // this not working
      data: [...prevState.data,
      {
        "userId": 1,
        "id": 2,
        "title": "Two New",
        "body": "new data"
      }
      ]
    }))
  };

如果项目已经存在，我该如何更新？

Answer 1

您可以找到该项目并使用 object.assign 简单地更新它

let newUser1 = {
        "userId": 1,
        "id": 2,
        "title": "Two New",
        "body": "new data"
      }

this.setState(prevState => {
    let newData = prevState.data;
    let user = newData.find(d => d.id === newUser1.id);
    Object.assign(user, newUser1);
    return {data: newData};
})