React报错信息之Expected an assignment or function call and instead saw an expression

// App.js

const App = props => {
  const result = ['a', 'b', 'c'].map(el => {
    // ⛔️ Expected an assignment or function call and instead saw an expression. eslint no-unused-expressions
    el + '100';
  });

  return <div>hello world</div>;
};

const mapStateToProps = (state) => {
  // ⛔️ Expected an assignment or function call and instead saw an expression. eslint no-unused-expressions
  todos: ['walk the dog', 'buy groceries']
}

export default App;

const App = props => {
  const result = ['a', 'b', 'c'].map(el => {
    return el + '100'; // 👈️ using explicit return
  });

  console.log(result);

  return <div>hello world</div>;
};

const mapStateToProps = state => {
  return {todos: ['walk the dog', 'buy groceries']}; // 👈️ using explicit return
};

export default App;

// 👇️ implicit return
const App = props => (
  <div>
    <h2>hello</h2>
    <h2>world</h2>
    {['a', 'b', 'c'].map(element => (
      <div key={element}>{element}</div>
    ))}
  </div>
);

// 👇️ implicit return
const result = ['a', 'b', 'c'].map(element => element + '100');
console.log(result); // 👉️ ['a100', 'b100', 'c100']

// 👇️ implicit return
const mapStateToProps = state => ({
  todos: ['walk the dog', 'buy groceries'],
});

export default App;

// ✅ RIGHT
const mapStateToProps = state => ({
  todos: ['walk the dog', 'buy groceries'],
});

// ⛔️ WRONG
const msp = state => {
  // ⛔️ Expected an assignment or function call and instead saw an expression.eslint no-unused-expressions
  todos: ['walk the dog', 'buy groceries']
};

{
  console.log('this is my block of code');
}

// eslint-disable-next-line no-unused-expressions