GraphJS
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GraphJS is a simple Javascript library for manipulating directed and undirected graphs.
Your graphs may have self edges, weighted edges, and directed edges, but not multiedges.
Usage
Creating, reading, updating, and deleting edges (CRUD)
var g = new Graph();
g.set('a', 'b', 3); # creates edge (a, b) with weight 3
g.get('a', 'b'); # returns 3
g.set('a', 'b', 4); # changes (a, b) weight to 4
g.get('a', 'b'); # returns 4
g.del('a', 'b'); # removes edge (a, b)
g.get('a', 'b'); # returns undefined
Constructing graphs from data
new Graph({
a: ['b', 'c'],
c: ['d'],
}); # triangle with vertices a, b, and c
new Graph({
a: {b: 2},
b: {c: 3},
}); # path with vertices a, b, c and weights (a, b) = 2, (b, c) = 3
With directed edges
new Graph({a: ['-b', '-c']}); # Directed edges to b and c.
Degree, size, order, and adjacency
var g = new Graph({
a: ['b'],
b: ['c'],
}); # path with vertices a, b, c
g.degree('a'); # returns 1
g.degree('b'); # returns 2
g.degree('c'); # returns 1
g.size(); # returns 2, the number of edges
g.order(); # returns 3, the number of vertices
for (v in g.adj('b')) {
# v = a, c (in no particular order)
}
Creating directed edges
var g = new Graph();
g.dir('a', 'b'); # a ~ b, but b !~ a
g.has('a', 'b'); # true
g.has('b', 'a'); # false
Alternative syntax
g.set('a', '-b'); # Same as g.dir('a', 'b');
Deleting directed edges
var g = new Graph();
g.set('a', 'b'); # a ~ b, and b ~ a
g.deldir('b', 'a'); # remove b ~ a
g.has('a', 'b'); # true
g.has('b', 'a'); # false
Copying
var g = new Graph({
a: ['b', 'c'],
c: ['d'],
});
var h = g.copy(); # an independent copy of g
Directed edges and graph size
You may mix directed and undirected edges in the same graph.
A pair of directed edges (a, b) and (b, a) is always collapsed into an undirected edge. An undirected edge (a, b) may be expanded into a directed edge (a, b) by deleting the directed edge (b, a) with deldir(b, a)
.
For consistency, the size of a graph is defined to be the number of undirected edges plus the number of directed edges. In other words, two distinct directed edges between two distinct vertices do not count twice for the size.
A directed self edge is indistinguishable from an undirected self edge.
Tests
GraphJS is packaged with nodeunit
tests.
The easiest way to run the tests is with npm test
.
$ npm test
...
OK: 173 assertions (23ms)
You can also test your browser by loading the test.html
page.