Fix formatting of empty type parameters

[fisker]

Description

Fixes #13817

Checklist

• I’ve added tests to confirm my change works.
• (If changing the API or CLI) I’ve documented the changes I’ve made (in the docs/ directory).
• (If the change is user-facing) I’ve added my changes to changelog_unreleased/*/XXXX.md file following changelog_unreleased/TEMPLATE.md.
• I’ve read the contributing guidelines.

✨Try the playground for this PR✨

[fisker]

Update:

Sorry, I got it wrong, the isArrowFunctionVariable check is not the problem.

---

@thorn0 This regression introduced in #11515, so I guess we should add name check instead of move .length === 0 out? 07d8883

But changed output of #11515

[thorn0]

The name check shouldn't affect anything as far as I can see. A VariableDeclarator node has only two subnodes: init and id. It's already known that init is an arrow function. So an Identifier node can only be id.
update: I see, you've figured it out

[thorn0]

This is not ideal but not critical either.

Prettier pr-14073
Playground link

--parser flow
--print-width 65

Input:

const MyComponent2: React.VoidFunctionComponent<
  /*MyComponent2Props*/
> = ({ x, y }) => {
  const a = useA();
  return (
    <div>
      x = {x}; y = {y}; a = {a}
    </div>
  );
};

Output:

const MyComponent2: React.VoidFunctionComponent</*MyComponent2Props*/> =
  ({ x, y }) => {
    const a = useA();
    return (
      <div>
        x = {x}; y = {y}; a = {a}
      </div>
    );
  };

[fisker]

Multi line comment can get ugly.

Prettier pr-14073
Playground link

--parser flow
--print-width 65

Input:

const MyComponent2: React.VoidFunctionComponent<
  /*
  MyComponent2Props
  */
> = ({ x, y }) => {
  const a = useA();
  return (
    <div>
      x = {x}; y = {y}; a = {a}
    </div>
  );
};

Output:

const MyComponent2: React.VoidFunctionComponent</*
  MyComponent2Props
  */> = ({ x, y }) => {
  const a = useA();
  return (
    <div>
      x = {x}; y = {y}; a = {a}
    </div>
  );
};