Guides

Leaderboards and saves

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A leaderboard and saved progress without a server of your own. Submit scores, show the top 50, and keep progress in cloud storage so it follows players to any phone.

#A leaderboard

board.js

async function gameOver(score) {
  const { best } = await Lia.submitScore(score);
  if (score === best) Lia.haptic("success");
  showBoard(await Lia.leaderboard());
}

function showBoard({ top, me }) {
  list.innerHTML = top
    .map((row) => `<li class="${row.me ? "me" : ""}"><b>${row.rank}</b> @${escapeHtml(row.name)} <span>${row.score}</span></li>`)
    .join("");
  if (me && me.rank > top.length) footer.textContent = `You: #${me.rank} with ${me.score}`;
}

Escape names before putting them in HTML, as with any text from people.

Each app has one leaderboard, with each player's best. Scores are whole numbers and higher is better; for a time or "fewest moves", submit something like 1000000 - milliseconds.

#Saved progress

Cloud storage keeps up to 1024 keys per player in your app on Lia's server, and follows them to any phone.

save.js

const SAVE = "save";

async function load() {
  const text = await Lia.cloudStorage.getItem(SAVE);
  return text ? JSON.parse(text) : { level: 1, coins: 0 };
}

let saving = null;
function save(state) {
  // Coalesce saves: at most one write every 2 seconds.
  clearTimeout(saving);
  saving = setTimeout(function () {
    Lia.cloudStorage.setItem(SAVE, JSON.stringify(state)).catch(function () {
      Lia.deviceStorage.setItem(SAVE, JSON.stringify(state)); // keep it on the phone meanwhile
    });
  }, 2000);
}

Lia.onPause(function () { /* save now: they may not come back */ });

Values are up to 4096 characters, so keep big things (a level editor's maps, say) on your own server or split them across keys and read them back with getItems.

#What goes where

Keep it in	When
`Lia.cloudStorage`	Progress, settings and anything the player expects on a new phone
`Lia.deviceStorage`	Caches, drafts and anything you can lose (up to 5 MB)
`Lia.secureStorage`	A token for your own server (up to 10 items)
Your own server	Anything that's worth money or decides prizes, coins bought with $LIA, and what other players see

Cloud storage is the player's to change from your page, so treat it like anything from the page: fine for their own progress, not for balances. Test and live share it.