Group nodes by child & parent taxonothe with Views – Drupal 7

Here is what you can do:

Fetch games when component is mounted. And Submit new game when form is submitted.

export default function App() {
  const [data, setData] = useState([])
  const [formData, setFormData] = useState('')

  useEffect(() => {
    fetchGames() // Fetch games when component is mounted
  }, [])

  const fetchGames = () => {
    fetch('http://localhost:3000/game', {
      method: 'GET',
    })
      .then((res) => res.json())
      .then((result) => setData(result.rows))
      .catch((err) => console.log('error'))
  }

  const saveGames = () => {
    fetch('http://localhost:3000/game', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        name: formData, // Use your own property name / key
      }),
    })
      .then((res) => res.json())
      .then((result) => setData(result.rows))
      .catch((err) => console.log('error'))
  }

  const handleSubmit = (event) => {
    event.preventDefault()
    saveGames() // Save games when form is submitted
  }

  const handleChange = (event) => {
    setFormData(event.target.value)
  }

  return (
    <div className="App">
      {/* method="post" not needed here because `fetch` is doing the POST not the `form` */}
      {/* Also, note I changed the function name, handleSubmit */}
      <form onSubmit={handleSubmit}>
        <input type="text" name="name" value={formData} onChange={handleChange} />
        <button type="submit">click</button>
      </form>

      {data &&
        data.map((element, index) => (
          <GameTestResult name={element.name} key={element.index} />
        ))}
    </div>
  )
}

You can read this about how to use fetch and this about how forms work in RecatJS.

After googling the whole afternoon (and posting it there), I eventually found the answer.

It's based on a tutorial on scito.ch (thanks), with only a few modifications. On the Content: Has taxonomy term ID (with depth) filter, be sure to check the Allow multiple values checkbox. Also (there's a lot of wrong tuts for that), don't specify anything in the WHEN THE FILTER VALUE IS AVAILABLE OR A DEFAULT IS PROVIDED. It's important you specify all those 3 contextual filters.

Hope this helps someone and saves him a sunny afternoon :)