[verified] Snake 0.7: queued controls, records, pause and wrap mode

src/common/best.js

@@ -0,0 +1,63 @@
+// Vela storage callbacks return raw strings, not { data } wrappers.
+// https://iot.mi.com/vela/quickapp/en/features/data/storage.html
+function createStore(storage) {
+  let value = 0
+  let saved = 0
+  let loaded = false
+  let reading = false
+  let writing = false
+  let listener = null
+  function notify() { if (listener) listener(value) }
+  function flush() {
+    if (!loaded || writing || value <= saved) return
+    writing = true
+    const target = value
+    let settled = false
+    const fail = () => { if (!settled) { settled = true; writing = false } }
+    try {
+      storage.set({ key: 'snake.best', value: String(target), success() {
+        if (settled) return
+        settled = true
+        writing = false
+        saved = target
+        flush()
+      }, fail })
+    } catch (e) { fail() }
+  }
+  function sync() {
+    if (loaded) { flush(); return }
+    if (reading) return
+    reading = true
+    let settled = false
+    const fail = () => { if (!settled) { settled = true; reading = false } }
+    try {
+      storage.get({ key: 'snake.best', default: '0', success(raw) {
+        if (settled) return
+        settled = true
+        reading = false
+        const n = Number(raw)
+        saved = Number.isInteger(n) && n >= 0 && n <= 253 ? n : 0
+        value = Math.max(value, saved)
+        loaded = true
+        notify()
+        flush()
+      }, fail })
+    } catch (e) { fail() }
+  }
+  return {
+    subscribe(fn) { listener = fn; notify() },
+    record(score) { value = Math.max(value, score); notify(); sync() },
+    sync
+  }
+}
+// One coordinator per native storage module, retained across page recreation.
+let sharedAPI
+let sharedStore
+function getStore(storage) {
+  if (storage !== sharedAPI) {
+    sharedAPI = storage
+    sharedStore = createStore(storage)
+  }
+  return sharedStore
+}
+module.exports = { getStore }