crates/loro-wasm/README.md
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Loro is a CRDTs(Conflict-free Replicated Data Types) library that makes building local-first and collaborative apps easier. You can now use it in Rust, JS (via WASM), and Swift.
Features Provided by CRDTs
Supported CRDT Algorithms
Advanced Features in Loro
In this example, we demonstrate importing an entire Loro codebase into a Loro-powered version controller, preserving the complete Git DAG history while enabling fast version switching.
The standard build pipeline (deno run -A ./scripts/build.ts dev|release) now keeps DWARF debugging information through wasm-bindgen and emits two helper files alongside every loro_wasm_bg.wasm artifact:
loro_wasm_bg.wasm.map β a v3 source map derived from DWARF so that Chrome, Edge, and Firefox can show original Rust locations when inspecting stack traces.Load the source map in browser devtools; when devtools fetches the debug companion it can map instructions back to Rust source files and line numbers without inflating the shipped .wasm.
import { expect, test } from 'vitest';
import { LoroDoc, LoroList } from 'loro-crdt';
test('sync example', () => {
// Sync two docs with two rounds of exchanges
// Initialize document A
const docA = new LoroDoc();
const listA: LoroList = docA.getList('list');
listA.insert(0, 'A');
listA.insert(1, 'B');
listA.insert(2, 'C');
// Export all updates from docA
const bytes: Uint8Array = docA.export({ mode: 'update' });
// Simulate sending `bytes` across the network to another peer, B
const docB = new LoroDoc();
// Peer B imports the updates from A
docB.import(bytes);
// B's state matches A's state
expect(docB.toJSON()).toStrictEqual({
list: ['A', 'B', 'C'],
});
// Get the current version of docB
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 sync point
const bytesB: Uint8Array = docB.export({ mode: 'update', from: version });
// Simulate sending `bytesB` back across the network to A
// A imports the updates from B
docA.import(bytesB);
// A has the same state as B
expect(docA.toJSON()).toStrictEqual({
list: ['A', 'C'],
});
});
Loro draws inspiration from the innovative work of the following projects and individuals: