Implement storage logic

Use storage functions in implementations.

src/Storage.ts

@@ -1,7 +1,7 @@
 import Storage, { Collection, OutOfSyncError } from '../../core/src/storage'
 import Engine from './Engine'
 
-export default class LocalStorage<T> implements Storage<T> {
+export default class LocalStorage<T = unknown> implements Storage<T> {
   private readonly engine: Engine<Collection<T>>
 
   constructor(

src/index.ts

@@ -1,13 +1,56 @@
-import { Plugin } from '../../core/src/plugin'
+import { Plugin, StoragePlugin, } from '../../core/src/plugin'
 import Storage from './Storage'
 
-type PluginConfig = {}
+type PluginConfig = {
+  idAttribute?: string,
+}
+
+const AVAILABLE_COLLECTIONS = ['notes', 'folders'] as const
+
+const localStorageFactory: Plugin<PluginConfig> = ({
+  idAttribute = 'id',
+} = {}) => class LocalStorage implements StoragePlugin {
+  private readonly storageMap: Record<string, Storage>
+
+  public static readonly type: 'storage'
+
+  constructor({ currentUserId, }) {
+    this.storageMap = AVAILABLE_COLLECTIONS.reduce(
+      (theStorages, collectionId) => ({
+        ...theStorages,
+        [collectionId]: new Storage(currentUserId, collectionId)
+      }),
+      {}
+    )
+  }
+
+  async save(collectionId, item) {
+    const { [collectionId]: storage = null } = this.storageMap
+    if (storage === null) {
+      throw new Error(`Invalid collection "${collectionId}"`)
+    }
+    return storage.saveItem(item)
+  }
+
+  async load(collectionId, itemId) {
+    const { [collectionId]: storage = null } = this.storageMap
+    if (storage === null) {
+      throw new Error(`Invalid collection "${collectionId}"`)
+    }
+    const items = await storage.queryItems()
+    if (!itemId) {
+      return items
+    }
+    return items.filter(i => i[idAttribute] === itemId)
+  }
 
-const LocalStoragePlugin: Plugin<PluginConfig> = config => ({
-  currentUserId,
-}) => {
-  new Storage(currentUserId, 'notes')
-  new Storage(currentUserId, 'folders')
+  async remove(collectionId, item) {
+    const { [collectionId]: storage = null } = this.storageMap
+    if (storage === null) {
+      throw new Error(`Invalid collection "${collectionId}"`)
+    }
+    return storage.deleteItem(item)
+  }
 }
 
-export default LocalStoragePlugin
+export default localStorageFactory