Are parentheses needed around the returned object in an arrow function in JavaScript?

Question

In the React docs, I came across this example of an arrow function. After the =>, the state object is wrapped in parentheses. Are they necessary? And, if so, do the parentheses change how the arrow function works?

Different than?:

this.setState((prevState, props) => {
    //code
});

Would the code without the parentheses run properly?

Answer 1

The sample code returns an object.

The longer version would be:

this.setState((prevState, props) => {
  return { counter: ... };
});