Graphs


This library contain an implementation of graph data structure
with various method that can be useful in operations by graphs.

Graphs can directed and undirected, weighted and unweighted.
So we have 4 variations and this library can works with them.

Install

``
npm install graphs-all
`

Getting Started

Import the library

`javascript
var graphs = require("graphs-all");
var g = graphs.UndirectedUnweightedGraph();
g.addNode("A");
g.addLink("A", "B");
g.addLink("A", "C");
g.addLink("B", "C");
g.hasNode("C") // true
g.hasLink("B", "A") // true
g.removeLink("C", "A");
g.connectedWith("B") // ["A", "B"]
`

$3

You can create four variations of graphs with shortcuts functions:

`javascript
var simpleGraph = graphs.UndirectedUnweightedGraph(),
directedGraph = graphs.DirectedUnweightedGraph(),
weightedGraph = graph.UndirectedWeightedGraph(),
complexGraph = graph.DirectedWeightedGraph();
`

Or with Graph class:

new Graph(isDirected, isWeighted)

`javascript
var simpleGraph = new graphs.Graph(false, false),
directedGraph = new graphs.Graph(true, false),
weightedGraph = new graphs.Graph(false, true),
complexGraph = new graphs.Graph(true, true);
`

$3

Graph.addNode(nodeKey)

Add a node in the graph with key nodeKey. If node is exist already,
then return false, for successive addition returns true.

`javascript
simpleGraph.addNode("A")
simpleGraph.hasNode("B") // true
simpleGraph.hasNode("A") // false
`

$3

Graph.hasNode(nodeKey)

Check is a node with key nodekey in the graph

`javascript
simpleGraph.hasNode("A") // true
simpleGraph.hasNode("E") // false
`

$3

Graph.addLink(key1, key2)

Graph.addLink(key1, key2, weight)

Add a link between key1 and key2 nodes. If nodes are not existed, then they are created.
For directed graphs, it's created a directed link from key1 to key2.
For weighted graphs you can add the third argument weight (default == 1).
weight must be a number.

`javascript
simpleGraph.addLink("A", "E");
simpleGraph.hasNode("E"); // true
weightedGraph.addLink("E", "C", 5);
`

$3

Graph.hasLink(key1, key2)

Graph.linkWeight(key1, key2)

Check the existence of the link between key1 and key2 nodes (the order is important only for directed graphs).
It returns true if the link is exist, false otherwise.

Also you can use linkWeight - it has the same interface and returns undefined if the link doesn't exist,
otherwise the weight of the link (1 for unweighted graphs).

`javascript
simpleGraph.addLink("A", "E");
simpleGraph.hasLink("E", "A"); // true
weightedGraph.addLink("E", "C", 5);
weightedGraph.linkWeight("E", "C"); // 5
simpleGraph.linkWeight("Z", "A"); // undefined
`

$3

Graph.nodes()

Returns an array on node keys.

`javascript
simpleGraph.addLink(1, 2);
simpleGraph.addLink(3, 4);
simpleGraph.nodes(); // [1, 2, 3, 4]
`

$3

Graph.connectedWith(key)

Returns an array of keys of nodes, which are connected with the given node.
For directed graphs return only nodes that are available from from the given node.

`javascript
simpleGraph.addLink("A", "D");
simpleGraph.addLink("A", "E");
simpleGraph.addLink("C", "A");
simpleGraph.nodeConnections("A"); // ["E", D", "C"]

directedGraph.addLink("A", "B");
directedGraph.addLink("C", "A");
directedGraph.nodeConnections("A"); // ["B"]
`

$3

Graph.removeNode(key)

Removes the node from the graph, also remove all connected links (input and output).

`javascript
directedGraph.addLink("1", "2");
directedGraph.addLink("3", "1");
directedGraph.addLink("1", "4");
directedGraph.removeNode("1");
directedGraph.hasNode("1"); // false
directedGraph.hasLink("1", "2"); // false
directedGraph.hasLink("3", "1"); // false
`

$3

Graph.removeLink(key1, key2)

Removes the link from the graph. The nodes are not removed, only the link.
For directed graphs remove only one-way link from key1 to key2.

`javascript
simpleGraph.addLink("5", "6");
simpleGraph.removeLink("6", "5");
simpleGraph.hasLink("5", "6"); // false
simpleGraph.hasNode("5"); // true
``