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)
[](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
// 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.
