use Proxy for db

background/background.js

@@ -38,11 +38,7 @@ addAPI(/** @namespace API */ {
     },
   }))(),
 
-  /** @type IDBObjectStore */
+  drafts: db.open('drafts'),
-  drafts: new Proxy({}, {
-    get: (_, cmd) => (...args) => db.exec.call('drafts', cmd, ...args),
-  }),
-
   styles: styleMan,
   sync: syncMan,
   updater: updateMan,

background/db-chrome-storage.js

@@ -4,6 +4,8 @@
 /* exported createChromeStorageDB */
 function createChromeStorageDB(PREFIX) {
   let INC;
+  const isMain = !PREFIX;
+  if (!PREFIX) PREFIX = 'style-';
 
   return {
 
@@ -19,7 +21,9 @@ function createChromeStorageDB(PREFIX) {
       const all = await chromeLocal.get();
       if (!INC) prepareInc(all);
       return Object.entries(all)
-        .map(([key, val]) => key.startsWith(PREFIX) && Number(key.slice(PREFIX.length)) && val)
+        .map(([key, val]) => key.startsWith(PREFIX) &&
+          (!isMain || Number(key.slice(PREFIX.length))) &&
+          val)
         .filter(Boolean);
     },
 

background/db.js

@@ -11,16 +11,28 @@
 
 /* exported db */
 const db = (() => {
-  const DATABASE = 'stylish';
+  let exec = async (...args) => (
-  const STORE = 'styles';
+    exec = await tryUsingIndexedDB().catch(useChromeStorage)
+  )(...args);
+  const DB = 'stylish';
   const FALLBACK = 'dbInChromeStorage';
-  const dbApi = {
+  const proxies = {};
-    async exec(...args) {
+  const proxyHandler = {
-      dbApi.exec = await tryUsingIndexedDB().catch(useChromeStorage);
+    get: ({dbName}, cmd) => (...args) => exec(dbName, cmd, ...args),
-      return dbApi.exec(...args);
+  };
-    },
+  const getProxy = (dbName = DB) =>
+    /** @type {IDBObjectStore | {putMany: function(items:?[]):Promise<?[]>}} */
+    proxies[dbName] || (
+      proxies[dbName] = new Proxy({dbName}, proxyHandler)
+    );
+  const getStoreName = dbName =>
+    dbName === DB
+      ? 'styles'
+      : 'data';
+  return {
+    styles: getProxy(),
+    open: getProxy,
   };
-  return dbApi;
 
   async function tryUsingIndexedDB() {
     // we use chrome.storage.local fallback if IndexedDB doesn't save data,
@@ -40,9 +52,9 @@ const db = (() => {
 
   async function testDB() {
     const id = `${performance.now()}.${Math.random()}.${Date.now()}`;
-    await dbExecIndexedDB('put', {id});
+    await dbExecIndexedDB(DB, 'put', {id});
-    const e = await dbExecIndexedDB('get', id);
+    const e = await dbExecIndexedDB(DB, 'get', id);
-    await dbExecIndexedDB('delete', e.id); // throws if `e` or id is null
+    await dbExecIndexedDB(DB, 'delete', e.id); // throws if `e` or id is null
   }
 
   async function useChromeStorage(err) {
@@ -53,17 +65,17 @@ const db = (() => {
     }
     await require(['/background/db-chrome-storage']); /* global createChromeStorageDB */
     const BASES = {};
-    return function dbExecChromeStorage(method, ...args) {
+    return (dbName, method, ...args) => (
-      const prefix = Object(this) instanceof String ? `${this}-` : 'style-';
+      BASES[dbName] || (
-      const baseApi = BASES[prefix] || (BASES[prefix] = createChromeStorageDB(prefix));
+        BASES[dbName] = createChromeStorageDB(dbName !== DB && `${dbName}-`)
-      return baseApi[method](...args);
+      )
-    };
+    )[method](...args);
   }
 
-  async function dbExecIndexedDB(method, ...args) {
+  async function dbExecIndexedDB(dbName, method, ...args) {
     const mode = method.startsWith('get') ? 'readonly' : 'readwrite';
-    const dbName = Object(this) instanceof String ? `${this}` : DATABASE;
+    const storeName = getStoreName(dbName);
-    const store = (await open(dbName)).transaction([STORE], mode).objectStore(STORE);
+    const store = (await open(dbName)).transaction([storeName], mode).objectStore(storeName);
     const fn = method === 'putMany' ? putMany : storeRequest;
     return fn(store, method, ...args);
   }
@@ -92,7 +104,8 @@ const db = (() => {
 
   function create(event) {
     if (event.oldVersion === 0) {
-      event.target.result.createObjectStore(STORE, {
+      const idb = event.target.result;
+      idb.createObjectStore(getStoreName(idb.name), {
         keyPath: 'id',
         autoIncrement: true,
       });

background/style-manager.js

@@ -105,7 +105,7 @@ const styleMan = (() => {
       if (ready.then) await ready;
       const data = id2data(id);
       const {style, appliesTo} = data;
-      await db.exec('delete', id);
+      db.styles.delete(id);
       if (reason !== 'sync') {
         API.sync.delete(style._id, Date.now());
       }
@@ -251,7 +251,7 @@ const styleMan = (() => {
           await usercssMan.buildCode(style);
         }
       }
-      const events = await db.exec('putMany', items);
+      const events = await db.styles.putMany(items);
       return Promise.all(items.map((item, i) =>
         handleSave(item, {reason: 'import'}, events[i])
       ));
@@ -437,7 +437,7 @@ const styleMan = (() => {
 
   async function saveStyle(style, handlingOptions) {
     beforeSave(style);
-    const newId = await db.exec('put', style);
+    const newId = await db.styles.put(style);
     return handleSave(style, handlingOptions, newId);
   }
 
@@ -477,10 +477,10 @@ const styleMan = (() => {
   }
 
   async function init() {
-    const styles = await db.exec('getAll') || [];
+    const styles = await db.styles.getAll() || [];
     const updated = await Promise.all(styles.map(fixKnownProblems).filter(Boolean));
     if (updated.length) {
-      await db.exec('putMany', updated);
+      await db.styles.putMany(updated);
     }
     styles.forEach(storeInMap);
     ready = true;

background/sync-manager.js

@@ -209,7 +209,7 @@ const syncMan = (() => {
           }
         }
         if (diff < 0) {
-          doc.id = await db.exec('put', doc);
+          doc.id = await db.styles.put(doc);
           uuidIndex.set(doc._id, doc.id);
           return styleUtil.handleSave(doc, {reason: 'sync'});
         }

background/update-manager.js

@@ -234,7 +234,7 @@ const updateMan = (() => {
       if (err && etag && !style.etag) {
         // first check of ETAG, gonna write it directly to DB as it's too trivial to sync or announce
         style.etag = etag;
-        await db.exec('put', style);
+        await db.styles.put(style);
       }
       return err
         ? Promise.reject(err)