如何在TypeScript React组件中返回字符串或JSX元素？

import React from 'react';

class MyComponent extends React.Component {
  render() {
    return "Hello, World!";
  }
}

import React from 'react';

class MyComponent extends React.Component {
  render() {
    return <div>Hello, World!</div>;
  }
}

import React from 'react';

class MyComponent extends React.Component {
  render() {
    const isLoggedIn = true;
    
    if (isLoggedIn) {
      return <div>Welcome back, user!</div>;
    } else {
      return <div>Please log in.</div>;
    }
  }
}

import React from 'react';

class MyComponent extends React.Component {
  render() {
    return (
      <React.Fragment>
        <h1>Title</h1>
        <p>Paragraph 1</p>
        <p>Paragraph 2</p>
      </React.Fragment>
    );
  }
}