graph-utils

What is it?

install

npm i --S graph-utils

usage

graph api

The fundamental entry point is a graph.

const grutils = require('graph-utils')

const g = new grutils.Graph()

Graph.addVertex(id:String, data:*=null):Vertex

Adds a new vertex to the graph and returns the reference.

v = g.addVertex('1', 'foo')

g.vertices // { '1': Vertex { } }

v.id // '1'
v._ // 'foo'
v.edges.outgoing // []
v.edges.incoming // []

Graph.getVertex(id:String):Vertex

Get a reference to the Vertex with vertex.id === id. Note that at the current time there is no equivalent getEdge(id:String) api.

g.getVertex('1') // v { id: '1', _: 'foo' }

Graph.addEdge(weight:Number, sourceId:String, targetId:String, data:*=null):Edge

Adds a new edge to the graph originating from one vertex to another. At your option, you may add some metadata to the edge.

v1 = g.addVertex('1', 'SanFrancisco')
v2 = g.addVertex('2', 'Oakland')

e1 = g.addEdge(3.1, v1.id, v2.id, 'Bay Bridge')

e1._  // 'Bay Bridge'
e1.weight // 3.1
e1.source // '1'
e1.target // '2'

g.edges // [e]
v1.edges.outgoing // [e]
v2.edges.incoming // [e]

Graph.removeEdge(edge:Edge):Edge

Remove an edge from the graph by reference. The edge will be unlinked from edge.source and edge.target.

// Bye-bye Bay Bridge!
g.removeEdge(e1)

g.edges // []
v1.edges.outgoing // []
v2.edges.incoming // []

Graph.removeVertex(vertex:Vertex):Vertex

Remove a vertex from the graph by reference. Note that all edges that have this vertex as edge.source or edge.target will be removed from the graph as well.

v1 = g.addVertex('1', 'SanFrancisco')
v2 = g.addVertex('2', 'Oakland')

e1 = g.addEdge(3.1, v1.id, v2.id, 'Bay Bridge')

// Bye-bye Oakland and Bay Bridge!
g.removeVertex(v2)

g.edges // []
g.vertices // { '1': Vertex { } }

v1.edges.outgoing // []

Graph.setEdge(weight:Number, sourceId:String, sourceIndex:Number, targetId:String, targetIndex:Number=0, data:*=null)

Replace a specific edge(s) in the graph: g.getVertex(sourceId).edges.outgoing[sourceIndex] and link the new edge to g.getVertex(targetId).edges.incoming[targetIndex]. You shouldn't need to call this directly, but it is used by the Tree/TreeNode implementation under the covers. See the lib/node.js for more details.

tree/tree node api

The fundamental entries are trees and nodes, respectively. Underneath the hood the tree is implemented as a graph and unfortunately it is required to pass the reference to the underlying Graph object as the first parameter when constructing new trees and nodes. Note that the underlying vertex of a node has a reference to the node in vertex._.

const grutils = require('graph-utils')

const g = new grutils.Graph()
const tree = new grutils.Tree(g, '1', { 'foo': 'bar' })
const node1 = new grutils.Node(g, '2', 'baz')

tree.root // Node { id: '1', _: { 'foo': 'bar' } }
node1 // Node { id: '2', _: 'baz' }

g.vertices // { '1': Vertex { }, '2': Vertex { } }

tree.root.left = node1

tree.root.left // Node { id: '2', _: 'baz' }

g.edges // [ Edge { weight: 1, source: '1', target: '2' } ]

Note that while some core functionality is there, this project is still very much a work in progress.

How do I work on it?

development

git clone https://github.com/sterpe/graph-utils.git
cd graph-utils
make

build

make build

test

make JEST_FLAGS=--coverage test

lint

make lint

Consult the Makefile for further details.