loro/README.md

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  <a href="https://loro.dev">
    <picture>
      <img src="./docs/Loro.svg" width="200"/>
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<h1 align="center">
<a href="https://loro.dev" alt="loro-site">Loro</a>
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<p align="center">
  <b>Reimagine state management with CRDTs 🦜</b><br/>
  Make your app state synchronized and collaborative effortlessly.
</p>
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  <a href="https://trendshift.io/repositories/4964" target="_blank"><img src="https://trendshift.io/api/badge/repositories/4964" alt="loro-dev%2Floro | Trendshift" style="width: 250px; height: 55px;" width="250" height="55"/></a>
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  <a href="https://loro.dev/docs">
    <b>Documentation</b>
  </a>
  |
  <a href="https://loro.dev/docs/tutorial/get_started">
    <b>Getting Started</b>
  </a>
  |
  <a href="https://docs.rs/loro">
    <b>Rust Doc</b>
  </a>
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https://github.com/loro-dev/loro/assets/18425020/fe246c47-a120-44b3-91d4-1e7232a5b4ac


> ⚠️ **Notice**: The current API and encoding schema of Loro are **experimental** and **subject to change**. You should not use it in production. 

Loro is a [CRDTs(Conflict-free Replicated Data Types)](https://crdt.tech/) library that makes building [local-first apps][local-first] easier. It is currently available for JavaScript (via WASM) and Rust developers. 

Explore our vision in our blog: [**✨ Reimagine State Management with CRDTs**](https://loro.dev/blog/loro-now-open-source).

# Features

**Basic Features Provided by CRDTs**

- P2P Synchronization
- Automatic Merging
- Local Availability
- Scalability
- Delta Updates

**Supported CRDT Algorithms**

- 📝 Text Editing with [Fugue]
- 📙 [Peritext-like Rich Text CRDT](https://loro.dev/blog/loro-richtext)
- 🌲 [Moveable Tree](https://loro.dev/docs/tutorial/tree)
- 🚗 [Moveable List](https://loro.dev/docs/tutorial/list)
- 🗺️ [Last-Write-Wins Map](https://loro.dev/docs/tutorial/map)
- 🔄 [Replayable Event Graph](https://loro.dev/docs/advanced/replayable_event_graph)

**Advanced Features in Loro**

- 📖 Preserve Editing History in a [Replayable Event Graph](https://loro.dev/docs/advanced/replayable_event_graph)
- ⏱️ Fast [Time Travel](https://loro.dev/docs/tutorial/time_travel) Through History

https://github.com/loro-dev/loro/assets/18425020/ec2d20a3-3d8c-4483-a601-b200243c9792

# Example

[![Open in StackBlitz](https://developer.stackblitz.com/img/open_in_stackblitz.svg)](https://stackblitz.com/edit/loro-basic-test?file=test%2Floro-sync.test.ts)

```ts
import { expect, test } from 'vitest';
import { Loro, LoroList } from 'loro-crdt';

/**
 * Demonstrates synchronization of two documents with two rounds of exchanges.
 */
// Initialize document A
const docA = new Loro();
const listA: LoroList = docA.getList('list');
listA.insert(0, 'A');
listA.insert(1, 'B');
listA.insert(2, 'C');

// Export the state of document A as a byte array
const bytes: Uint8Array = docA.exportFrom();

// Simulate sending `bytes` across the network to another peer, B
const docB = new Loro();
// Peer B imports the updates from A
docB.import(bytes);

// Verify that B's state matches A's state
expect(docB.toJSON()).toStrictEqual({
  list: ['A', 'B', 'C'],
});

// Get the current operation log version of document B
const version = docB.oplogVersion();

// Simulate editing at B: delete item 'B'
const listB: LoroList = docB.getList('list');
listB.delete(1, 1);

// Export the updates from B since the last synchronization point
const bytesB: Uint8Array = docB.exportFrom(version);

// Simulate sending `bytesB` back across the network to A
// A imports the updates from B
docA.import(bytesB);

// Verify that the list at A now matches the list at B after merging
expect(docA.toJSON()).toStrictEqual({
  list: ['A', 'C'],
});
```

# Credits

Loro draws inspiration from the innovative work of the following projects and individuals:

- [Ink & Switch](https://inkandswitch.com/): The principles of Local-first Software have greatly influenced this project. The [Peritext](https://www.inkandswitch.com/peritext/) project has also shaped our approach to rich text CRDTs.
- [Diamond-types](https://github.com/josephg/diamond-types): The [Replayable Event Graph (REG)](https://loro.dev/docs/advanced/replayable_event_graph) algorithm from @josephg has been adapted to reduce the computation and space usage of CRDTs.
- [Automerge](https://github.com/automerge/automerge): Their use of columnar encoding for CRDTs has informed our strategies for efficient data encoding.
- [Yjs](https://github.com/yjs/yjs): We have incorporated a similar algorithm for effectively merging collaborative editing operations, thanks to their pioneering works.
- [Matthew Weidner](https://mattweidner.com/): His work on the [Fugue](https://arxiv.org/abs/2305.00583) algorithm has been invaluable, enhancing our text editing capabilities.
- [Martin Kleppmann](https://martin.kleppmann.com/): His work on CRDTs has significantly influenced our comprehension of the field.
 

[local-first]: https://www.inkandswitch.com/local-first/
[Fugue]: https://arxiv.org/abs/2305.00583
[Peritext]: https://www.inkandswitch.com/peritext/