y-memory

8.0.9 verified Sat May 09 auth: no javascript

In-memory database adapter for Yjs, version 8.0.9. It provides a lightweight, ephemeral storage backend for collaborative editing with Yjs, discarding all data upon session end. Best for prototyping or stateless scenarios. Works in all browsers with fast access. Unlike persistent adapters (e.g., y-leveldb), it requires no external database setup. Released under MIT.

Common errors

error Error: Cannot find module 'y-memory' ↓

cause Missing import or npm install.

fix

Run npm install y-memory and add import 'y-memory' at the top of your file.

error TypeError: Y is not a function ↓

cause Trying to use Y() constructor in Yjs v13+ where it's removed.

fix

Use new Y.Doc() instead of Y({...}).

error Error: Yjs version must be between 9.0.0 and 14.0.0 ↓

cause Incompatible Yjs version.

fix

Update Yjs to version 9.0.0-13.x.x with npm install yjs@^13.0.0.

Warnings

deprecated The Y() constructor with db adapter config is deprecated; use Y.Doc() directly in Yjs v13+. ↓

fix Use `new Y.Doc()` and manage persistence separately.

gotcha Data is lost when page is refreshed; memory adapter does not persist. ↓

fix Use a persistent adapter like y-indexeddb or y-leveldb for permanent storage.

breaking y-memory v8 only works with Yjs >=9.0.0 <14.0.0; older versions incompatible. ↓

fix Ensure Yjs version is >=9.0.0 and <14.0.0.

deprecated Bower installation is deprecated; use npm or yarn. ↓

fix Use `npm install y-memory` instead.

Install

npm install y-memory

yarn add y-memory

pnpm add y-memory

Imports

y-memory
wrong
```
const memory = require('y-memory')
```
correct
```
import 'y-memory'
```
y-memory is a side-effect module that registers itself as a Yjs db adapter; no named export needed.
Yjs
wrong
```
const Y = require('yjs')
```
correct
```
import * as Y from 'yjs'
```
Yjs mainly supports ESM; CommonJS might cause issues with bundlers.
Y
wrong
```
new Yjs({ db: { name: 'memory' } })
```
correct
```
Y({ db: { name: 'memory' } })
```
Yjs is initialized via a function call to Y(), not as a constructor.

Quickstart

Shows how to import y-memory and use it with Yjs to create an in-memory document and manipulate a shared array.

// Install: npm install yjs y-memory
import * as Y from 'yjs';
import 'y-memory';

// Initialize Yjs with memory adapter
const y = new Y.Doc();
const yarray = y.getArray('myarray');
yarray.insert(0, ['hello']);

// Or use the legacy Y() constructor (deprecated but still works)
// Y({ db: { name: 'memory' } }).then(y => { ... });

console.log(yarray.toArray()); // ['hello']