无法在react UI上显示javascript函数的返回值

import React, { useState } from 'react';

function MyComponent() {
  const [result, setResult] = useState('');

  const myFunction = () => {
    const returnValue = someFunction(); // 调用你的JavaScript函数
    setResult(returnValue);
  };

  return (
    <div>
      <button onClick={myFunction}>执行函数</button>
      <p>返回值：{result}</p>
    </div>
  );
}

import React, { useState, useEffect } from 'react';

function MyComponent() {
  const [result, setResult] = useState('');

  useEffect(() => {
    const returnValue = someFunction(); // 调用你的JavaScript函数
    setResult(returnValue);
  }, []);

  return (
    <div>
      <p>返回值：{result}</p>
    </div>
  );
}

import React, { Component } from 'react';

class MyComponent extends Component {
  constructor(props) {
    super(props);
    this.state = {
      result: ''
    };
  }

  componentDidMount() {
    const returnValue = someFunction(); // 调用你的JavaScript函数
    this.setState({ result: returnValue });
  }

  render() {
    return (
      <div>
        <p>返回值：{this.state.result}</p>
      </div>
    );
  }
}