@ocap/indexdb-fs/lib/table/base.js

OCAP indexdb adapter that uses file system as backend

/* eslint-disable no-underscore-dangle */
const path = require('path');
const { BaseIndex } = require('@ocap/indexdb');
const Lokijs = require('lokijs');
const FsAdapter = require('lokijs/src/loki-fs-structured-adapter');

const debug = require('debug')(require('../../package.json').name);

class FsIndex extends BaseIndex {
  constructor(name, dataDir, uniqIndex) {
    super(name, uniqIndex);

    this.name = name;
    this.uniqIndex = uniqIndex;
    this.collection = null;

    const adapter = new FsAdapter();
    const db = new Lokijs(path.join(dataDir, `${name}.db`), {
      adapter,
      autoload: true,
      autosave: true,
      autosaveInterval: 1000,
      autoloadCallback: () => {
        this.collection = db.getCollection(name);

        if (this.collection === null) {
          this.collection = db.addCollection(name, { unique: [this.primaryKey], clone: true });
        }

        this.markReady();
      },
    });
    this.db = db;
  }

  count(...args) {
    return this.collection.count(...args);
  }

  _insert(row) {
    const id = this.generatePrimaryKey(row);
    // Don't call this._get here cause _get may be overwritten
    const doc = FsIndex.prototype._get.call(this, id);
    if (doc) {
      return doc;
    }

    debug(`insert ${this.name}`, row);
    return this.collection.insert({ [this.primaryKey]: id, ...row });
  }

  _get(key) {
    const id = this.generatePrimaryKey(key);
    return key ? this.collection.by(this.primaryKey, id) : null;
  }

  _update(key, updates) {
    const id = this.generatePrimaryKey(key);
    // Don't call this._get here cause _get may be overwritten
    const doc = FsIndex.prototype._get.call(this, id);
    if (!doc) {
      return null;
    }

    debug(`update ${this.name}`, { id, key, updates });

    Object.assign(doc, updates);
    this.collection.update(doc);
    return doc;
  }

  _reset() {
    this.collection.removeWhere({});
  }
}

module.exports = FsIndex;