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README.md

@codemix/y-graph-storage

A Yjs storage adapter for @codemix/graph that persists the graph inside a Y.Doc, enabling real-time collaborative graph editing, CRDT-based conflict resolution, live reactive queries, and support for rich Yjs shared types (Y.Text, Y.Array, Y.Map) as property values.

Part of the codemix product intelligence platform.

Table of Contents

Features

  • CRDT-backed persistence — all graph data lives inside a Y.Doc; merges are automatic and conflict-free.
  • Real-time collaboration — plug in any Yjs provider (WebSocket, WebRTC, IndexedDB, …) and every peer sees the same graph with no extra code.
  • Reactive change events — subscribe to fine-grained events: vertex.added, vertex.deleted, edge.added, edge.deleted, vertex.property.set, vertex.property.changed, and edge equivalents.
  • Live queries — a LiveQuery wraps a traversal and re-fires whenever a relevant change occurs.
  • Rich Yjs property types — use Y.Text, Y.Array<T>, and Y.Map<V> as property values with built-in Zod schema helpers that convert plain values transparently.
  • Full @codemix/graph API — YGraph extends Graph, so every traversal, Cypher query, and index feature works unchanged.

Installation

npm install @codemix/y-graph-storage yjs
# or
pnpm add @codemix/y-graph-storage yjs

@codemix/graph is a peer dependency and must also be installed.

Quick Start

import * as Y from "yjs";
import * as z from "zod";
import { GraphSchema, GraphTraversal } from "@codemix/graph";
import { YGraph, ZodYText } from "@codemix/y-graph-storage";

const schema = {
  vertices: {
    Person: {
      properties: {
        name: { type: ZodYText }, // stored as Y.Text
        age: { type: z.number() },
      },
    },
  },
  edges: {
    knows: { properties: {} },
  },
} as const satisfies GraphSchema;

const doc = new Y.Doc();
const graph = new YGraph({ schema, doc });

const alice = graph.addVertex("Person", { name: new Y.Text("Alice"), age: 30 });
const bob = graph.addVertex("Person", { name: new Y.Text("Bob"), age: 25 });
graph.addEdge(alice, "knows", bob, {});

// Read a collaborative text property
alice.get("name").toString(); // "Alice"

// Traverse with the standard API
const g = new GraphTraversal(graph);
for (const path of g.V().hasLabel("Person").out("knows")) {
  console.log(path.value.get("name").toString()); // "Bob"
}

How It Works

YGraphStorage maps the graph onto a Y.Doc using shared Y.Map collections:

  • Each vertex label gets a top-level Y.Map keyed V:<Label>. The map's values are per-vertex Y.Map instances whose keys are the vertex UUID and whose values are the property values.
  • Each edge label gets a top-level Y.Map keyed E:<Label>. Each edge Y.Map stores @inV (target element ID), @outV (source element ID), and all edge properties.
  • Incoming/outgoing edge adjacency is stored inside each vertex Y.Map under the internal keys @inE and @outE as nested Y.Map<edgeId, true>. This avoids full scans when traversing neighbours.

Because everything is a native Yjs shared type, any two peers that apply the same set of operations will converge to the same state.

YGraph wraps YGraphStorage and the base Graph class. It also manages a shared Observable stream of YGraphChange events that powers subscriptions and live queries.

YGraph

Creating a YGraph

import * as Y from "yjs";
import { YGraph } from "@codemix/y-graph-storage";

const doc = new Y.Doc();
const graph = new YGraph({ schema, doc });

YGraph accepts:

Option Type Description
schema GraphSchema The graph schema (vertex/edge labels and property types).
doc Y.Doc The Yjs document. Provide a shared instance to sync with providers.

Mutating the Graph

YGraph inherits the full Graph mutation API. All mutations are automatically wrapped in a Y.Doc transaction:

// Add vertices
const alice = graph.addVertex("Person", { name: new Y.Text("Alice"), age: 30 });

// Add edges
const edge = graph.addEdge(alice, "knows", bob, {});

// Update a scalar property
graph.updateProperty(alice, "age", 31);
// or
alice.set("age", 31);

// Mutate a Y.Text property in place (triggers vertex.property.changed)
const name = alice.get("name");
name.delete(0, name.length);
name.insert(0, "Alicia");

// Delete
graph.deleteEdge(edge);
graph.deleteVertex(alice); // also cleans up attached edges

Traversals and Queries

Any @codemix/graph traversal or Cypher query runs unchanged:

import { GraphTraversal, parseQueryToSteps, createTraverser } from "@codemix/graph";

// Fluent traversal
const g = new GraphTraversal(graph);
const results = Array.from(g.V().hasLabel("Person").out("knows").values("name"));

// Cypher
const { steps, postprocess } = parseQueryToSteps(
  "MATCH (a:Person)-[:knows]->(b:Person) RETURN a.name, b.name",
);
const traverser = createTraverser(steps);
for (const row of traverser.traverse(graph, [])) {
  console.log(postprocess(row));
}

Subscribing to Changes

YGraph.subscribe returns a function that, when called, unsubscribes:

const unsubscribe = graph.subscribe({
  next(change) {
    console.log(change.kind, change.id);
  },
});

graph.addVertex("Person", { name: new Y.Text("Charlie"), age: 22 });
// logs: "vertex.added" "Person:<uuid>"

unsubscribe();

Multiple subscribe calls share a single underlying Yjs observeDeep listener; it is set up on the first call and torn down when the last subscriber unsubscribes.

Change Events

kind Extra fields Description
vertex.added id A vertex was inserted.
vertex.deleted id A vertex was removed.
edge.added id An edge was inserted.
edge.deleted id An edge was removed.
vertex.property.set id, property A scalar property was set on a vertex.
vertex.property.changed id, property, path, event A Yjs shared-type property (e.g. Y.Text) was mutated internally.
edge.property.set id, property A scalar property was set on an edge.
edge.property.changed id, property, path, event A Yjs shared-type property on an edge was mutated.

Live Queries

YGraph.query wraps a traversal in a LiveQuery that re-fires its subscription whenever a change could affect the result set:

const people = graph.query((g) => g.V().hasLabel("Person"));

// Initial traversal
for (const path of people) {
  console.log(path.value.get("name").toString());
}

// React to changes
const unsubscribe = people.subscribe({
  next(change) {
    // Re-run the traversal when relevant
    for (const path of people) {
      console.log("updated:", path.value.get("name").toString());
    }
  },
});

graph.addVertex("Person", { name: new Y.Text("Dave"), age: 28 });
// triggers subscriber

unsubscribe();

LiveQuery analyses the traversal steps to determine which change kinds are relevant. A FetchVerticesStep filtered by label only fires on vertex.added/vertex.deleted events for that label; a FilterElementsStep (e.g. has(…)) also watches vertex.property.set events; edge traversal steps watch edge.added/edge.deleted.

Yjs Shared Types as Properties

When properties need collaborative editing (e.g. a text field that multiple users can type into simultaneously), declare them with the Zod helpers exported from this package. Each helper accepts either the native Yjs type or a plain JS equivalent, and always outputs the Yjs type — so you can seed the graph with plain values and they will be converted automatically.

ZodYText

Accepts Y.Text or string, always stores a Y.Text.

import { ZodYText } from "@codemix/y-graph-storage";

const schema = {
  vertices: {
    Document: {
      properties: {
        title: { type: ZodYText },
        content: { type: ZodYText },
      },
    },
  },
  edges: {},
} as const satisfies GraphSchema;

const doc = graph.addVertex("Document", {
  title: "My Doc", // string → Y.Text
  content: new Y.Text("..."), // Y.Text → Y.Text (unchanged)
});

// Collaborative edit
doc.get("content").insert(0, "Hello, ");

ZodYArray

import { ZodYArray, ZodYText } from "@codemix/y-graph-storage";
import * as z from "zod";

const Tags = ZodYArray(z.string()); // Y.Array<string>
const Lines = ZodYArray(ZodYText); // Y.Array<Y.Text>

// In a schema:
tags: {
  type: Tags;
}

// Usage — accepts native array or Y.Array:
graph.addVertex("Post", { tags: ["crdt", "graph"] }); // converted
graph.addVertex("Post", { tags: Y.Array.from(["crdt"]) }); // stored as-is

post.get("tags").push(["realtime"]);

ZodYMap

import { ZodYMap } from "@codemix/y-graph-storage";
import * as z from "zod";

const Metadata = ZodYMap(z.string()); // Y.Map<string>

metadata: {
  type: Metadata;
}

// Accepts plain object or Y.Map:
graph.addVertex("Asset", { metadata: { author: "Alice" } });

asset.get("metadata").set("version", "2");

ZodYXmlFragment / ZodYXmlText / ZodYXmlElement

For rich-text or structured XML content:

import { ZodYXmlFragment, ZodYXmlText, ZodYXmlElement } from "@codemix/y-graph-storage";

body: {
  type: ZodYXmlFragment;
} // accepts string, outputs Y.XmlFragment
Helper Input Output
ZodYText string | Y.Text Y.Text
ZodYArray(schema) T[] | Y.Array<T> Y.Array<T>
ZodYMap(schema) Record<string, V> | Y.Map<V> Y.Map<V>
ZodYXmlFragment string | Y.XmlFragment Y.XmlFragment
ZodYXmlText string | Y.XmlText Y.XmlText
ZodYXmlElement {tag, attrs?, children?} | Y.XmlElement Y.XmlElement

Syncing with Yjs Providers

Because all data lives in a Y.Doc, you can connect any standard Yjs provider and get real-time sync for free:

import * as Y from "yjs";
import { WebsocketProvider } from "y-websocket";
import { YGraph } from "@codemix/y-graph-storage";

const doc = new Y.Doc();
const provider = new WebsocketProvider("wss://my-server", "my-room", doc);
const graph = new YGraph({ schema, doc });

// On every connected peer, graph mutations propagate automatically.
// Changes from remote peers emit YGraphChange events via graph.subscribe().

Other providers work the same way: y-indexeddb for offline persistence, y-webrtc for peer-to-peer, y-leveldb for Node.js, etc.

Low-level: YGraphStorage

If you need direct access to the storage layer — for example, to register custom Yjs observers or to inspect the raw Y.Map collections — use YGraphStorage directly:

import * as Y from "yjs";
import { YGraphStorage } from "@codemix/y-graph-storage";
import { Graph } from "@codemix/graph";

const doc = new Y.Doc();
const storage = new YGraphStorage(doc, { schema });
const graph = new Graph({ schema, storage });

// Access raw collections
const personCollection = storage.getVertexCollectionMap("Person");
const knowsCollection = storage.getEdgeCollectionMap("knows");

// Observe at the Yjs level
personCollection.observeDeep((events) => {
  for (const event of events) {
    console.log("raw yjs event", event);
  }
});

YGraphStorage implements the GraphStorage interface from @codemix/graph and can be used wherever a GraphStorage is accepted.

Internal Y.Doc Layout

Understanding the layout can help when debugging or building custom tooling.

Y.Doc key Type Contents
V:<Label> Y.Map<Y.Map<unknown>> All vertices of label <Label>. Keyed by UUID.
E:<Label> Y.Map<Y.Map<unknown>> All edges of label <Label>. Keyed by UUID.

Each vertex Y.Map contains:

Key Value Description
<propertyName> any Yjs-compatible value The vertex's properties.
@inE Y.Map<edgeId, true> IDs of incoming edges (populated when an edge targeting this vertex is added).
@outE Y.Map<edgeId, true> IDs of outgoing edges (populated when an edge originating from this vertex is added).

Each edge Y.Map contains:

Key Value Description
@inV ElementId Target vertex ID.
@outV ElementId Source vertex ID.
<propertyName> any Yjs-compatible value The edge's properties.

Internal keys all start with @ and are skipped by the change observer so they never surface as property.set/property.changed events.