React Functional Component:如何从useEffect()外部访问变量

import React, { useEffect } from 'react';

const MyComponent = () => {
  const myVariable = 'Hello World';

  useEffect(() => {
    console.log(myVariable);
  }, []);

  return <div>My Component</div>;
};

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

const MyComponent = () => {
  const myVariableRef = useRef(null);
  myVariableRef.current = 'Hello World';

  useEffect(() => {
    console.log(myVariableRef.current);
  }, []);

  return <div>My Component</div>;
};

import React, { useEffect } from 'react';

const MyComponent = () => {
  const myVariable = 'Hello World';

  useEffect(() => {
    const doSomething = () => {
      console.log(myVariable);
    };

    doSomething();
  }, []);

  return <div>My Component</div>;
};