GD Graph

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

1. The data store is immutable and functional so side effects aren't a problem.
2. The interface is entirely functional and has some useful introspection tools like 'has()', 'connected()', 'degree()'
3. 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.
4. 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.
5. 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)