@mathquis/modelx-leveldb-connector v0.2.0

LevelDB compatible connector for ModelX

:warning: ModelX uses MobX v5 new Proxy feature. This feature is only supported by recent browsers https://caniuse.com/#feat=proxy

Installation

npm install -D @mathquis/modelx-leveldb-connector

Usage

The LevelDBConnector accepts a required storage option defining the underlying LevelDB compatible API storage mechanism used to persist models. You can use any storage that implements the LevelDB API.

import {Model, Collection} from '@mathquis/modelx';
import LevelDBConnector from '@mathquis/modelx-leveldb-connector';

const db = level('./db');
const levelDB = new LevelDBConnector({storage: db});

class User extends Model {
	static get path(): string {
		return '/users/{id}';
	}
	static get connector(): Connector {
		return levelDB;
	}
}

// We create a new User model
const user = new User({
	id: 1,
	lastName: 'Doe',
	firstName: 'John'
});

user.save()
.then((model: Model) => {
	// My model is now created on the API
	return model.destroy();
})
.then((model: Model) => {
	// My model is now deleted from the API
});

const users = new Collection( User );

users.list().then((collection: Collection) => {
	console.log(collection.length);
});

Filtering

The LevelDBConnector supports filters in list() using MongoDB query selectors.

const col = new Collection( User );

// List only admin users created before 10/5/2018 at 5:43PM
col.list({
	filters: {
		type: {
			$eq: 'admin'
		},
		createdAt: {
			$lt: 1538747016000
		}
	}
});

Pagination

The LevelDBConnector supports pagination using the offset and limit options of the list() method.

const col = new Collection( User );

// List only admin users created before 10/5/2018 at 5:43PM
col.list({
	offset: 20,
	limit: 10
});

Generated model ID

If the model does not have an id when saving, the connector will generate one using the function provided in the id option. If no function is provided, a UUID (using the uuid module) will be generated.

let autoIncrement = 0;

const constructor = new LevelDBConnector({
	id: () => ++autoIncrement
});

const user = new User();

user.save(); // user.id will be be automatically set to 1

const user2 = new User();

user2.save(); // user2.id will be automatically set to 2

Prefixing

The LevelDBConnector accepts a prefix option to automatically prefix all keys in the web storage. This can help avoid collision between multiple instance of the connector.

const connector = new LevelDBConnector({
	prefix: '/namespace-a'
});

Performance

The LevelDBConnector allows to limit the maximum number of records parsed during a list() using the max option of the constructor or of the list() method.