alexeld/graph

Simple library for graph manipulations

#graph

Simple library for graph manipulations.

I need some graph-related operations for other project, so I decided to move them to separate module.

It is not intended to be full-featured graph manupulation (at least for now) but pull requests are welcome.

It will develop as my requirements will get more sophisticated.

Don't use it for large graphs — it uses array's .filter() methods to scan for nodes and edges, so it could be slow on large structures.

Installation

npm install node-graph

Usage

###new Graph(structure)

Returns graph instance.

var Graph = require('node-graph');

var structure = {
    nodes: [
        {
            name: 'A'
        },
        {
            name: 'B',
            youCanPutArbitraryDataOnYourNodes: { ... }
        }
    ],
    edges: [
        {
            name: 'A->B',
            from: 'A',
            to: 'B',
            youCanPutArbitraryDataOnYourEdgesToo: { ... }
        }
    ]
}

var gr = new Graph(structure);

Constructor checks that argument conforms to graph JSON schema (locates in schema/graph.json).

tl;dr It requires name field for nodes and name, from, to fields for edges. Also it checks for name uniqueness amongst edges and nodes respectively. Then is checks that every edge points to existing nodes (from and to fields containing valid node names).

###outboundEdges(node)

Returns array of edges that came out of specified node:

// You can pick outbound edges by node name
var outboundEdges = gr.outboundEdges('B');

// Or providing node object
var node = gr.getNode('B');
var outboundEdges2 = gr.outboundEdges(node);

Result example:

[{"name":"BD","from":"B","to":"D"}]

###inboundEdges(node)

Returns array of edges that came in to specified node:

// You can pick outbound edges by node name
var inboundEdges = gr.inboundEdges('D');

// Or providing node object
var node = gr.getNode('D');
var inboundEdges2 = gr.inboundEdges(node);

Result example:

[
    {"name":"BD","from":"B","to":"D"},
    {"name":"CD","from":"C","to":"D"}
]

###isTerminalNode(node)

If there are no outbound edges from specified node, returns true, false otherwise.

    // using node object
    var node = gr.getNode('D');
    gr.isTerminalNode(node);
    
    // using node name
    gr.isTerminalNode('D');

##getNode(name)

Returns node object by its name.

##getEdge(name)

Returns edge object by its name.

##License

MIT