Orbit is a composable framework for orchestrating change processing, tracking, and synchronization across multiple data sources.

Orbit is written in Typescript and distributed on npm through the @orbit organization. Pre-built distributions are provided in several module formats and ES language levels.

Orbit is isomorphic - it can be run both in modern browsers as well as in the Node.js runtime.

Orbit was primarily designed as a data layer to support the needs of ambitious client-side web applications, including:

• Optimistic and pessimistic UX patterns.

• Pluggable sources that share common interfaces, to allow similar behavior on different devices.

• Connection durability by queueing and retrying requests.

• Application durability by persisting all transient state.

• Warm caches of data available immediately on startup.

• Client-first / serverless development.

• Custom request coordination across multiple sources, allowing for priority and fallback plans.

• Branching and merging of immutable data caches.

• Deterministic change tracking.

• Undo / redo editing support.

In order to meet these goals, many primitives were developed in Orbit that can be used in ways that go beyond these original use cases.

Orbit consists of the following core libraries:

• @orbit/core - A core set of primitives for performing, tracking, and responding to asynchronous tasks, including:

  • An event system that allows listeners to engage with the fulfillment of events by returning promises.

  • An asynchronous task processing queue.

  • A log that tracks a history of changes and allows for revision and interrogation.

  • A bucket interface for persisting state. Used by logs and queues.

• @orbit/data - Applies the core Orbit primitives to data sources. Includes the following elements:

  • A schema for defining models, including attributes and relationships.

  • Operations used to manipulate records (e.g. addRecord, removeRecord, addToHasMany, etc.).

  • Transforms, which are composed of any number of operations, and must be performed transactionally.

  • A query language that allows query expressions to be composed in a flexible AST form.

  • A base Source class that can be used to abstract any source of data. Sources can be decorated as pullable, pushable, queryable, syncable, and/or updatable - each decorator provides a unique interface that allows for transforms and queries to be applied as appropriate.

• @orbit/coordinator - A coordinator and set of coordination strategies for managing data flow and keeping @orbit/data sources in sync.

• @orbit/immutable - A lightweight library of immutable data structures.

• @orbit/utils - A common set of utility functions used by Orbit libraries.

Orbit provides the following sources for accessing and persisting data:

• @orbit/store - An in-memory data store that supports complex querying and updating. Because stores maintain data in immutable data structures, they can be efficiently forked. Forked stores can diverge from the master store, and then the changes can be merged later.

• @orbit/jsonapi - Provides full CRUD support, including complex querying, for a RESTful API that conforms to the JSON:API specification.

• @orbit/local-storage - Persists records to local storage.

• @orbit/indexeddb - Persists records to IndexedDB.

These standard sources can provide guidance for building your own custom sources as well.

Buckets are used to persist application state, such as queued requests and change logs. Standard buckets include:

• @orbit/local-storage-bucket - Persists state to local storage.

• @orbit/indexeddb-bucket - Persists state to IndexedDB.

Orbit's main packages are maintained in this "mono-repo" and managed by lerna.

Install the CLI for Broccoli globally:

npm install -g broccoli-cli

Install other dependencies:

npm install

Build distributions for all packages:

npm run build

Test all packages:

npm test

Or cd into each package's dir and test it individually in the browser:

cd packages/@orbit/core
testem

Copyright 2014-2017 Cerebris Corporation. MIT License (see LICENSE for details).