Display errors to users during self-selected network

[FedericoDM]

What Issue Are You Seeing or What Feature Needs To Be Added?

During the self-selected game, players are able to choose either two or three players to see their guesses during the game. However, there are several scenarios that we don't want to happen. Mainly, we don't want the player selecting the same person more than once.

I tried to implement a JavaScript (which is used during session creation) for this purpose, but I did not manage to make it work. The aim of this issue is to incorporate this feature on the template.

Are There Any Links That Would Be Helpful?

Here is the JavaScript:

PrijateliTree/prijateli_tree/app/templates/choose_neighbors.html

Lines 7 to 21 in 0105d91

	fetch('{{ url_for("create_session") }}', {
	method: 'POST',
	body: formData
	})
	.then(resp => {
	window.location.href = resp.url
	}) // or, resp.text(), etc
	.catch(error => {
	console.error(error);
	});
	function cleanParams() {
	// Used to clear the URL of parameters after the banner alert is closed.
	window.history.replaceState(null, '', window.location.pathname);
	}
	</script>