notesnook/packages/core/database/cached-collection.js

import IndexedCollection from "./indexed-collection";
import MapStub from "../utils/map";

export default class CachedCollection extends IndexedCollection {
  constructor(context, type, eventManager) {
    super(context, type, eventManager);
    this.type = type;
    this.map = new Map();
    this.items = undefined;
    // this.eventManager = eventManager;
    // this.encryptionKeyFactory = encryptionKeyFactory;
  }

  async init() {
    await super.init();
    let data = await this.indexer.readMulti(this.indexer.indices);
    if (this.map && this.map.dispose) this.map.dispose();

    // const encryptionKey =
    //   this.encryptionKeyFactory && (await this.encryptionKeyFactory());
    // if (encryptionKey) {
    //   for (let item of data) {
    //     const [_key, value] = item;
    //     const decryptedValue = JSON.parse(
    //       await this.indexer.decrypt(encryptionKey, value)
    //     );
    //     item[1] = decryptedValue;
    //   }
    // }

    this.map = new MapStub.Map(data, this.type);
  }

  async clear() {
    await super.clear();
    this.map.clear();
    this.invalidateCache();
  }

  async updateItem(item) {
    await super.updateItem(item);
    this.map.set(item.id, item);
    this.invalidateCache();
  }

  exists(id) {
    return this.map.has(id) && !this.map.get(id).deleted;
  }

  has(id) {
    return this.map.has(id);
  }

  getItem(id) {
    return this.map.get(id);
  }

  async deleteItem(id) {
    this.map.delete(id);
    await super.deleteItem(id);
    this.invalidateCache();
  }

  getRaw() {
    return Array.from(this.map.values());
  }

  getItems(map = undefined) {
    if (this.items) return this.items;

    this.items = [];
    this.map.forEach((value) => {
      if (!value || value.deleted || !value.id) return;
      value = map ? map(value) : value;
      this.items.push(value);
    });
    this.items.sort((a, b) => b.dateCreated - a.dateCreated);
    return this.items;
  }

  invalidateCache() {
    this.items = undefined;
  }
}