gd_graph

GD Graph

gd_graph is a simple tool for managing a directed graph and includes some nice features that help to manage the data:

• The data store is immutable and functional so side effects aren't a problem.
• The interface is entirely functional and has some useful introspection tools like 'has()', 'connected()', 'degree()'
• Generates and manages unique ids for all nodes across multiple graphs. Create as many graphs as you'd like and it won't create possible node id conflicts.
• No dependencies. This is intended to be simple and generic with minimal assumption about how it will be used. Possible uses are: scene graphs, games, logic models, data visualization, etc. gd_graph is intended to simplify some of the underlying logic associated with that type of data architecture.
• Small and lightweight.

Install

    npm install --save gd_graph

Tests

    npm test

Importing

    import graph from "gd_graph" // ES6
    // or
    var graph = require("../gd_graph.es5").default; // ES5

Create a graph.

    const g = graph()

Add nodes to the graph.

    // add nodes to the graph
    // they start out disconnected
    // returns id's for the nodes
    const id1 = g.add()
    const id2 = g.add()
    const id3 = g.add()
    const id4 = g.add()

Remove a node from the graph.

    // removes the node and all of its connections
    // cleans up connections from other nodes as well
    g.remove( id4 );

Add directional edges between graph nodes.

    // connect directional edge between nodes
    // returns true/false for connection success
    g.connect( id1, id2 ) //true
    g.connect( id1, id3 ) //true
    g.connect( id1, id4 ) //false

Add bidirectional edges between graph nodes. This will only connect unconnected edges.

    // bidirectionally connect nodes
    g.connectFull(id2, id3) //[true, true]
    g.connectFull(id1, id2) //[false, true]
    g.connectFull(id1, id4) //[false, false]

Other methods and tools for introspection

    // get a list of all node ids
    // unique ids are generated by the graph
    g.ids() // ["n0", "n1", "n2"]

    // get all the nodes and their edges
    g.nodes() // {n0:[], n1:[], n2:[]}
    
    // does a directional edge
    // connect the first node to the second
    g.connected( id1, id2 ) // true
    g.connected( id1, id3 ) // false
    g.connected( id3, id1 ) // false
    
    // does the graph contain a node with this id?
    g.has( id1 ) // true
    g.has( id4 ) // false

    // get the node's list of edges
    g.get( id1 ) // [ ids... ]
    g.get( id1 ) // [ ids... ]

    // how many connections has id1 formed with other nodes
    // convenience to get the length of the edge list for
    // this node
    g.degree( id1 ) // 3

    // removes the edge from id1 -> id2
    // returns true if the connection is severed
    // returns false if the sever fails
    g.sever( id1, id2 ) // true

    // removes the edge from id2 -> id3 and id3 -> id2
    // returns [true,true] if the connections are severed
    // returns [false, false] if the severs fail
    g.severFull(id2, id3)