matchmaking.md

Lobbies

Official reference: ISteamMatchmaking.

Lobby creation, joining, and listing use Steam call results, so await them with callback pumping. The returned objects contain the lobby ID and Steam result.

const { lobbyId } = await waitForSteamCall(
	matchmaking.createLobby(LobbyType.Public, 4),
);

matchmaking.setLobbyData(lobbyId, 'mode', 'co-op');
matchmaking.setLobbyJoinable(lobbyId, true);

joinLobby(lobbyId) and requestLobbyList() follow the same promise rule. Related callback events include lobby-created, lobby-enter, lobby-match-list, lobby-invite, and lobby-join-requested.

Synchronous lobby state

getLobbyByIndex(), getLobbyMemberByIndex(), getLobbyOwner(), and getLobbyDataByIndex() return null for an invalid or missing index. The string-returning getLobbyData() and getLobbyMemberData() use an empty string for an absent key. Update fields with setLobbyData(), deleteLobbyData(), setLobbyOwner(), setLobbyType(), setLobbyJoinable(), and setLobbyMemberLimit(); methods returning boolean report whether Steam accepted the change.

getNumLobbyMembers() and getLobbyMemberLimit() provide bounds for indexed reads. Use leaveLobby(lobbyId) when the session ends.

Lobby chat

Send binary data with sendLobbyChatMsg(lobbyId, Buffer.from(...)). On a lobby-chat-msg event, use the supplied chatId with getLobbyChatEntry(lobbyId, chatId, maximumMessageSize?). It returns null when Steam cannot read that entry; its data field is a Node.js Buffer.