Graph implementation with Typescript support.

I needed a graph library with Typescript support, as it often happens I could not find an exact match and decided to create my own.

The library implements an extended adjacent list algorithm. It might use a bit more memory in order to keep the additional information as trade off for more simplified graph operations.

The core graph class also implements a simple event emitter. This allows a simple notification in graph changes. It is a useful feature for integrating the library with other modules. For example I used this library in Vue-based flow-editor for updating reactive states:

const graph = new Graph({ opEvents: true });
const vertices = shallowRef(graph.vertices);
const edges = shallowRef(graph.nodes);

graph.on('changed', () => {
  vertices.value = graph.vertices;
  edges.value = graph.edges;
});

Installation

Add the library to your project either as a Commonjs module

<script src=""></script> 

Or as an ES module. Install first, using npm

npm install graph-typescript

using yarn

yarn add graph-typescript

Then import the module

import { Graph } from 'graph-typescript'

...

const Graph = require('graph-typescript')

Usage

The library provides three classes Graph, Vertex(node), and Edge(link) along with supporting types and utilities.

Graph class exposes all necessary methods for creating, updating or removing edges/vertices directly on the graph.

const graph = new Graph();

/**
 * Create a new vertex(node)
*/
const [vertex, error] = graph.createVertex(id, data);
if (error) {
  // handle error 
}

/**
 * Update the vertex(node)
*/
const [, error] = graph.updateVertex(vertex, data);

/**
 * Remove the vertex(node)
*/
const [,error] = graph.removeVertex(vertex);


/**
 * Create a new edge(link)
*/
const vertex1 = graph.vertices.find((vertex: Vertex) => vertex.idx === idx1);
const vertex2 = graph.vertices.find((vertex: Vertex) => vertex.idx === idx2);

const [edge, error] = graph.createEdge(vertex1, vertex2, data);

/**
 * Update the edge(link)
*/
const [, error] = graph.updateEdge(edge, data);

/**
 * Remove the edge(link)
*/
const[, error] = graph.removeEdge(edge);

Altertantively, Vertex and Edge classes can be used to instanciate new vertices or edges separetly however new instances must be added to the graph using either addVertex or addEdge methpds. It might be handy when you need to provision a temporally instance, e.g. a temporary edge between two vertices. Once the new instance is validated and confirmed it can be added to the graph.

More exemples