Storage

Storage allows us to create persistent data that multiple users can edit simultaneously. This is ideal for storing real-time document state, such as shapes on a canvas, paragraphs in a text editor, or cells in a spreadsheet.

Conflict-free data types

To build applications using storage, you can make use of our conflict-free data types. Each type is similar to a JavaScript counterpart:

• LiveObject - JavaScript Object
• LiveList - JavaScript Array
• LiveMap - JavaScript Map

These data types can be combined and nested, to create a real-time data structure that automatically updates when multiple users modify data at the same time, whilst handling any conflicts along the way.

Defining storage

Let’s imagine we were storing some data about a person, for example their name and age.

person: { name: "Marie", age: 30 }

To add this to storage, first we must define our types. Open liveblocks.config.ts and use a LiveObject with the structure for person as a generic.

// Storage typestype Storage = {  person: LiveObject<{    name: string;    age: number;  }>;};

Now we’ve defined the type, we can switch to App.tsx and add an intialStorage value, that is used when the room’s storage is created. We can match the Storage type by creating a new LiveObject.

<RoomProvider  id={roomId}  initialPresence={{}}  initialStorage={{    person: new LiveObject({ name: "Marie", age: 30 }),  }}>

Using a LiveObject like this, instead of a regular JavaScript object, allows us to use its real-time features. For example multiple people can edit the properties of a LiveObject at the same time without overriding the whole object.

Displaying storage

To use this real-time data in your app, we can import a hook named useStorage. This hook allows us to select part of our storage, before returning its value, and automatically updating on real-time changes.

// { person: "Marie", age: 30 }const person = useStorage((root) => root.person);

Each real-time data structure is converted to an immutable copy of its JavaScript counterpart, so a LiveObject becomes a regular JavaScript object. We can implement this ourselves by adding the following code to Room.tsx:

import { useStorage } from "./liveblocks.config";
export function Room() {  const person = useStorage((root) => root.person);
  return <div>Person: {JSON.stringify(person)}</div>;}

Press the refresh button in the preview window to reload initialStorage, and you should now be seeing person! On the next page we’ll be updating storage.