lokijs

What is lokijs?

LokiJS is an in-memory database that prioritizes performance and simplicity. It is written in JavaScript and can be used in web browsers, Node.js, and Cordova/PhoneGap applications. It offers a powerful query system and supports indexing for fast lookups.

What are lokijs's main functionalities?

In-memory database

LokiJS allows you to create an in-memory database, add collections, and insert documents.

const loki = require('lokijs');
const db = new loki('example.db');
const users = db.addCollection('users');
users.insert({ name: 'Odin', age: 1000 });
users.insert({ name: 'Thor', age: 30 });

Powerful query system

You can query the database using a MongoDB-like query syntax to retrieve data based on complex criteria.

const elderlyGods = users.find({ age: { '$gt': 500 } });

Indexing for fast lookups

LokiJS supports indexing of collections to enable faster query response times, especially beneficial for large datasets.

users.ensureIndex('age');
const youngGods = users.find({ age: { '$lte': 100 } });

Persistence adapters

LokiJS can be configured to use various persistence adapters, allowing you to save the database state to a file, local storage, or other storage systems.

const lokiFsAdapter = require('lokijs/src/loki-fs-structured-adapter');
const adapter = new lokiFsAdapter();
const db = new loki('example.db', { adapter: adapter });

Changes API

The Changes API allows you to listen for changes in the database, which can be used for syncing with a remote database or triggering other actions.

db.on('changes', function(changes) {
  console.log('Database changes:', changes);
});
users.insert({ name: 'Loki', age: 1042 });

Other packages similar to lokijs

nedb

NeDB is another lightweight JavaScript database, similar to LokiJS, that works both in Node.js and the browser. It also offers in-memory storage and has a MongoDB-like API. However, NeDB is no longer actively maintained.

pouchdb

PouchDB is a database that runs in the browser or in Node.js and is designed to sync with CouchDB. It offers similar query capabilities to LokiJS but focuses more on synchronization and offline-first applications.

rxdb

RxDB is a reactive database for JavaScript applications, which can be used in browsers, Node.js, and hybrid apps. It is built on top of PouchDB and offers real-time synchronization and event-driven data flows, which is different from LokiJS's approach.

lowdb

LowDB is a small local JSON database powered by Lodash, suitable for small projects (Node, Electron, and the browser). It is simpler than LokiJS and does not offer in-memory storage, but it is easy to use for small datasets and simple applications.

README

LokiJS

Overview

LokiJS is a document oriented client side database written in javascript. Its purpose is to store JSON documents in a mongodb fashion (the API is similar but not strictly compliant) and retrieve them with a similar mechanism. Runs in node and the browser. LokiJS is ideal for the following scenarios:

1. where a lightweight in-memory db is ideal
2. data sets are not so large that it wouldn't be a problem loading the entire db from a server and synchronising at the end of the work session
3. cross-platform mobile apps where you can leverage the power of javascript and avoid interacting with native databases

LokiJS has limited supports for indexing, transactions, couchdb-style views.

example usage here

Roadmap

In the near future mongodb-style dbRef will be implemented, wider and more specific support for indexes such as unique, compound.

License

Copyright (c) 2013, Joe Minichino [e-mail] All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by TechFort.
4. Neither the name of TechFort nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.