如何从一个对象中提取多个键并打印输出

Question

如何从事件处理程序中的对象打印多个键？

这里是链接到我的代码-https://codesandbox.io/s/suspicious-hamilton-erkqv

在第35行，我用对象“x”调用事件处理程序ChangeName。我可以打印一个名为“name”（x.name）的键。我如何打印x对象的所有3个道具（名称、id、类型）？？

尝试将x转换为object.keys（x）的数组，但当我循环通过输出时，它会给出一个错误，说不能使用map函数

 const ChangeName = x => {
    setvalue(x.name);
  };


  <div>{value}</div> // display the results

Answer 1

正在运行的代码：

import React, { useState, useEffect } from "react";
import ReactDOM from "react-dom";

function App() {
  const [posts, setposts] = useState([]);
  const [values, setvalue] = useState([]);

  useEffect(() => {
    const posts = [
      {
        id: 1,
        name: "Name 1",
        type: "Type 1"
      },
      {
        id: 2,
        name: "Name 2",
        type: "Type 2"
      },
      {
        id: 3,
        name: "Name 3",
        type: "Type 3"
      },
      {
        id: 4,
        name: "Name 4",
        type: "Type 4"
      }
    ];

    setposts(posts);
  }, []);

  const ChangeName = x => {
    console.log(Object.values(x));
    Object.values(x).map(k => setvalue(k));
  };

  return (
    <div>
      <ul>
        {posts.map(post => (
          <li key={post.id}>
            {post.name},{post.type}
            <button onClick={ChangeName.bind(this, post)}>More Info</button>
          </li>
        ))}
      </ul>

      <div>{values}</div>
    </div>
  );
}

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);

你需要设置值而不是值。

Answer 2

你的值不是一个数组，它是一个对象，为什么你不能使用map方法，这就是它的工作原理：

import React, { useState, useEffect } from "react";
import ReactDOM from "react-dom";

function App() {
  const [posts, setposts] = useState([]);
  const [value, setvalue] = useState("");

  useEffect(() => {
    const posts = [
      {
        id: 1,
        name: "Name 1",
        type: "Type 1"
      },
      {
        id: 2,
        name: "Name 2",
        type: "Type 2"
      },
      {
        id: 3,
        name: "Name 3",
        type: "Type 3"
      },
      {
        id: 4,
        name: "Name 4",
        type: "Type 4"
      }
    ];

    setposts(posts);
  }, []);

  const ChangeName = x => {
    setvalue(x);
  };

  return (
    <div>
      <ul>
        {posts.map(post => (
          <li key={post.id}>
            {post.name},{post.type}
            <button onClick={() => ChangeName(post)}>More Info</button>
          </li>
        ))}
      </ul>

      <div>
        {value.name}
        {value.id}
        {value.type}
      </div>
    </div>
  );
}

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);