问未处理的拒绝(TypeError)：无法读取未定义的属性“替换”

EN

 import React from "react";
import Sidebar from "./Sidebar";
import Feed from "./Feed";
import Widgets from "./Widgets";
import "./App.css";
import { MongoClient } from "mongodb";

function App() {
  // Connection URI
  const uri =
    "xxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
  // Create a new MongoClient
  const client = new MongoClient(uri);
  async function run() {
    try {
      // Connect the client to the server
      await client.connect();
      // Establish and verify connection
      await client.db("posts").command({ ping: 1 });
      console.log("Connected successfully to server");
    } finally {
      // Ensures that the client will close when you finish/error
      await client.close();
    }
  }
  run();

  return (
    <div className="app">
      <Sidebar />
      <Feed />
      <Widgets />
    </div>
  );
}

export default App;