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TimothyGillespieTimothyGillespie
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Add methods on Graph to receive incoming, outgoing and attached edges
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‎changelog.md

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# Version 0.4.0
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## New Features
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- added `getAttachedEdges(vertex: V)` method on `Graph`
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- added `getOutgoingEdges(vertex: V)` method on `Graph`
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- added `getIncomingEdges(vertex: V)` method on `Graph`
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# Version 0.3.1
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## Improvements

‎src/models/Graph/Graph.ts

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import { Vertex, vertexCompareTo, vertexEqual } from '../Vertex/Vertex/Vertex';
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import { Edge, edgeEqual } from '../Edge';
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import { Vertex, vertexCompareTo } from '../Vertex/Vertex/Vertex';
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import { Edge } from '../Edge';
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import * as cloneDeep from 'lodash.clonedeep';
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import { AdjacencyMatrix } from '../Matrix/AdjacencyMatrix';
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import { VertexNotFoundError } from '../../Errors';
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return this.getAdjacencyList().getAdjacentVertices(vertex);
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}
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getAttachedEdges(vertex: V): E[] {
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return this.getListOfEdges().filter(({vertexA, vertexB}) => {
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return vertexA.equals(vertex) || vertexB.equals(vertex);
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});
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}
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getOutgoingEdges(vertex: V): E[] {
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return this.getListOfEdges().filter(({vertexA, vertexB, isDirected}) => {
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if(isDirected()) {
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return vertexA.equals(vertex)
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}
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return vertexA.equals(vertex) || vertexB.equals(vertex);
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});
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}
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getIncomingEdges(vertex: V): E[] {
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return this.getListOfEdges().filter(({vertexA, vertexB, isDirected}) => {
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if(isDirected()) {
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return vertexB.equals(vertex)
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}
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return vertexA.equals(vertex) || vertexB.equals(vertex);
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});
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}
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getChildVertices(vertex: V): V[] {
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const allEdges = this.getListOfEdges();
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const allVertices = this.getListOfVertices();

‎src/models/Graph/__tests__/getAttachedAndIncomingAndOutgoingEdges.spec.ts

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import {Graph} from "../Graph";
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import {NamedVertex} from "../../Vertex/NamedVertex/NamedVertex";
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import {DirectedEdge, Edge, UndirectedEdge} from "../../Edge";
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import expectEdgeListsAreEqual from "../../../../testUtil/expectEdgeListsAreEqual";
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let graph: Graph<NamedVertex, Edge<NamedVertex>>;
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const a = new NamedVertex('a');
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const b = new NamedVertex('b');
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const c = new NamedVertex('c');
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const d = new NamedVertex('d');
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const e = new NamedVertex('e');
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const f = new NamedVertex('f');
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const g = new NamedVertex('g');
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const directedEdges = [
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new DirectedEdge(c, a),
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new DirectedEdge(c, b),
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new DirectedEdge(d, c),
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new DirectedEdge(e, c),
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new DirectedEdge(b, d),
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new DirectedEdge(d, b),
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new DirectedEdge(g, b),
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new DirectedEdge(g, d),
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];
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const undirectedEdges = [
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new UndirectedEdge(a, b),
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new UndirectedEdge(c, f),
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new UndirectedEdge(c, g),
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new UndirectedEdge(a, e),
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new UndirectedEdge(f, g),
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];
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describe('Test retrieving attached, incoming and outgoing edges for a vertex', () => {
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beforeEach(() => {
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graph = new Graph();
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graph.addVertex(a, b, c, d, e, f, g);
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});
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/*
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* Attached
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*/
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describe('g.getAttachedEdges(v)', () => {
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it('works with a directed graph', () => {
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graph.addEdge(...directedEdges);
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const attachedEdges = graph.getAttachedEdges(c);
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expectEdgeListsAreEqual(attachedEdges, [
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new DirectedEdge(c, a),
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new DirectedEdge(c, b),
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new DirectedEdge(d, c),
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new DirectedEdge(e, c),
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]);
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});
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it('works with an undirected graph', () => {
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graph.addEdge(...undirectedEdges);
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const attachedEdges = graph.getAttachedEdges(c);
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expectEdgeListsAreEqual(attachedEdges, [
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new UndirectedEdge(c, f),
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new UndirectedEdge(c, g),
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]);
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});
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it('works with a mixed direction graph', () => {
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graph.addEdge(...directedEdges, ...undirectedEdges);
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const attachedEdges = graph.getAttachedEdges(c);
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expectEdgeListsAreEqual(attachedEdges, [
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new DirectedEdge(c, a),
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new DirectedEdge(c, b),
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new DirectedEdge(d, c),
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new DirectedEdge(e, c),
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new UndirectedEdge(c, f),
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new UndirectedEdge(c, g),
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]);
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});
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});
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/*
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* Outgoing
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*/
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describe('g.getOutgoingEdges(v)', () => {
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it('works with a directed graph', () => {
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graph.addEdge(...directedEdges);
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const attachedEdges = graph.getOutgoingEdges(c);
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expectEdgeListsAreEqual(attachedEdges, [
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new DirectedEdge(c, a),
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new DirectedEdge(c, b),
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]);
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});
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it('works with an undirected graph', () => {
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graph.addEdge(...undirectedEdges);
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const attachedEdges = graph.getOutgoingEdges(c);
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expectEdgeListsAreEqual(attachedEdges, [
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new UndirectedEdge(c, f),
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new UndirectedEdge(c, g),
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]);
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});
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it('works with a mixed direction graph', () => {
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graph.addEdge(...directedEdges, ...undirectedEdges);
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const attachedEdges = graph.getOutgoingEdges(c);
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expectEdgeListsAreEqual(attachedEdges, [
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new DirectedEdge(c, a),
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new DirectedEdge(c, b),
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new UndirectedEdge(c, f),
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new UndirectedEdge(c, g),
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]);
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});
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});
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/*
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* Incoming
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*/
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describe('g.getIncomingEdges(v)', () => {
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it('works with a directed graph', () => {
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graph.addEdge(...directedEdges);
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const attachedEdges = graph.getIncomingEdges(c);
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expectEdgeListsAreEqual(attachedEdges, [
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new DirectedEdge(d, c),
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new DirectedEdge(e, c),
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]);
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});
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it('works with an undirected graph', () => {
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graph.addEdge(...undirectedEdges);
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const attachedEdges = graph.getIncomingEdges(c);
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expectEdgeListsAreEqual(attachedEdges, [
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new UndirectedEdge(c, f),
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new UndirectedEdge(c, g),
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]);
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});
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it('works with a mixed direction graph', () => {
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graph.addEdge(...directedEdges, ...undirectedEdges);
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const attachedEdges = graph.getIncomingEdges(c);
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expectEdgeListsAreEqual(attachedEdges, [
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new DirectedEdge(d, c),
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new DirectedEdge(e, c),
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new UndirectedEdge(c, f),
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new UndirectedEdge(c, g),
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]);
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});
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});
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});

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