Reactive Graph Matcher

A reactive graph engine built with Graphology that finds subgraph patterns and executes callbacks upon changes to the graph.

Installation

npm install reactive-graph-matcher

Quick Start

Here is a basic example of how to use the engine to find a pattern.

import { ReactivePatternMatcher, Pattern } from 'reactive-graph-matcher';

async function main() {
  const engine = new ReactivePatternMatcher();

  // 1. Define the pattern to find
  const knowsPattern: Pattern = {
    nodes: [
      { id: 'a', properties: { type: 'Person' } },
      { id: 'b', properties: { type: 'Person' } }
    ],
    edges: [
      { source: 'a', target: 'b', properties: { rel: 'KNOWS' } }
    ],
  };

  // 2. Register a callback for the pattern
  engine.onMatch(knowsPattern, (subgraph) => {
    const personA = subgraph.nodes.find(n => n.id.startsWith('Alice'));
    const personB = subgraph.nodes.find(n => n.id.startsWith('Bob'));
    
    if (personA && personB) {
      console.log(`${personA.id} knows ${personB.id}!`);
    }
  });
  
  // 3. Apply changes to the graph
  await engine.apply([
    { type: 'addNode', node: { id: 'Alice', type: 'Person' } },
    { type: 'addNode', node: { id: 'Bob', type: 'Person' } },
    { type: 'addEdge', source: 'Alice', target: 'Bob', attributes: { rel: 'KNOWS' } }
  ]);
  
  // Output: Alice knows Bob!
}

main();

API

new ReactivePatternMatcher()

Creates a new engine instance.

engine.apply(commands: UserCmd[]): Promise<void>

Applies a batch of commands to mutate the graph.

engine.onMatch(pattern: Pattern, callback: MatchCallback): void

Registers a pattern and a callback to be executed when a match is found.