graph.js是什么
什么是graph.js，a javascript library for storing arbitrary data in mathematical (di)graphs, as well as traversing and analyzing them in various ways (ECMAScript 6 Ready)
graph.js使用教程帮助文档
graph.js
formerly known as jsgraph
graph.js
is a javascript library for storing arbitrary data in mathematical (di)graphs, as well as traversing and analyzing them in various ways. It was originally created to track dependencies between options and modules. It is written in ECMAScript 6, but autogenerated ECMAScript 5 versions are shipped with it.
Feedback of any kind (questions, issues, pull requests) is greatly appreciated.
Installing graph.js
When running in an ECMAScript 5 environment, this library depends on the Babel ES6 polyfill. For your convenience, a standalone version of graph.js is available, which has the polyfill already baked in.
graph.js is available from NPM and Bower:
npm install graph.js save
bower install graph.js save
The Babel polyfill is not distributed through Bower. So Bower users have to either use the standalone version of graph.js, or get the polyfill from someplace else, like NPM.
Loading graph.js
The graph.js library supports all popular module systems: ECMAScript 6, CommonJS (Node.js, IO.js, browserify, webpack), AMD (RequireJS), and good oldfashioned HTML script tags.
import Graph from 'graph.js'; // the ES6 version is default // use Graph
var Graph = require('graph.js/dist/graph.full.js'); // use Graph
requirejs(['graph.js/dist/graph.full.js'], function (Graph) { // use Graph });
<script src="graph.js/dist/graph.full.js"></script> <script> // use Graph </script>
The dist
directory offers different files for use in different circumstances. Use the following table to determine which file to use in your situation.
File  Description 

graph.es6.js 
for use in an ECMAScript 6 context, e.g., a modern browser or transpiler 
graph.js , 

graph.min.js 
requires you to load the Babel polyfill yourself 
graph.full.js , 

graph.full.min.js 
already includes the Babel polyfill 
If you don't know which you need, you probably want graph.full.js
, because it will work outofthebox. But it is generally more elegant to load the polyfill yourself, especially if you use other libraries that also depend on it.
API Documentation
 Graph
 new Graph(...parts)
 instance
 .on(event, handler)
 .off(event, handler)
 .addNewVertex(key, [value])
 .setVertex(key, [value])
 .ensureVertex(key, [value])
 .addVertex(key, [value])
 .removeExistingVertex(key)
 .destroyExistingVertex(key)
 .removeVertex(key)
 .destroyVertex(key)
 .vertexCount() ⇒
number
 .hasVertex(key) ⇒
boolean
 .vertexValue(key) ⇒
*
 .addNewEdge(from, to, [value])
 .createNewEdge(from, to, [value])
 .setEdge(from, to, [value])
 .spanEdge(from, to, [value])
 .addEdge(from, to, [value])
 .ensureEdge(from, to, [value])
 .createEdge(from, to, [value])
 .removeExistingEdge(from, to)
 .removeEdge(from, to)
 .edgeCount() ⇒
number
 .hasEdge(from, to) ⇒
boolean
 .edgeValue(from, to) ⇒
*
 .vertices() ⇒
Iterator.<string, *>
 .@@iterator() ⇒
Iterator.<string, *>
 .edges() ⇒
Iterator.<string, string, *>
 .verticesFrom(from) ⇒
Iterator.<string, *, *>
 .verticesTo(to) ⇒
Iterator.<string, *, *>
 .verticesWithPathFrom(from) ⇒
Iterator.<string, *>
 .verticesWithPathTo(to) ⇒
Iterator.<string, *>
 .sources() ⇒
Iterator.<string, *>
 .sinks() ⇒
Iterator.<string, *>
 .vertices_topologically() ⇒
Iterator.<string, *>
 .clearEdges()
 .clear()
 .equals(other, [eqV], [eqE]) ⇒
boolean
 .cycles() ⇒
Iterator.<Array.<string>>
 .cycle() ⇒
Array
 .hasCycle() ⇒
boolean
 .paths(from, to) ⇒
Iterator.<Array.<string>>
 .path(from, to) ⇒
Array
 .hasPath(from, to) ⇒
boolean
 .outDegree(key) ⇒
number
 .inDegree(key) ⇒
number
 .degree(key) ⇒
number
 .mergeIn(other, [mV], [mE])
 .clone([trV], [trE]) ⇒
Graph
 .transitiveReduction([trV], [trE]) ⇒
Graph
 .contractPaths([isNexus])
 .toJSON()
 "vertexadded"
 "vertexremoved"
 "vertexmodified"
 "edgeadded"
 "edgeremoved"
 "edgemodified"
 static
 .fromJSON()
 .VertexExistsError ⇐
Error
 .vertices :
Set.<Array>
 .vertices :
 .VertexNotExistsError ⇐
Error
 .vertices :
Set.<string>
 .vertices :
 .EdgeExistsError ⇐
Error
 .edges :
Set.<Array>
 .edges :
 .EdgeNotExistsError ⇐
Error
 .edges :
Set.<Array.<string>>
 .edges :
 .HasConnectedEdgesError ⇐
EdgeExistsError
 .vertex :
string
 .edges :
Set.<Array>
 .vertex :
 .CycleError ⇐
Error
 .cycle :
Array.<string>
 .cycle :
 .BranchlessCycleError ⇐
CycleError
 .cycle :
Array.<string>
 .cycle :
Graph
The main class of this library, to be used for representing a mathematical (di)graph.
new Graph(...parts)
Constructor arguments can be used to supply initial vertices and edges.
Param  Type  Description 

...parts  Array.<Array> 
a short notation for vertices and edges to initially add to the graph; A vertex should be an array of the form [key, value] . An edge should be an array of the form [[from, to], value] . Later values of vertices or edges in this list will overwrite earlier values, but vertices need not precede their edges. Vertices that are connected but store no value need not be listed at all. 
Example
var map = new Graph( ['Amsterdam', { population: 825000 }], // vertex ['Leiden', { population: 122000 }], // vertex [['Amsterdam', 'Leiden'], { distance: "40km" }] // edge );
graph.on(event, handler)
Register an event handler.
Param  Type  Description 

event  string 
the event to listen for 
handler  function 
the function to call for each such event fired, receiving its corresponding value 
graph.off(event, handler)
Deregister a previously registered event handler.
Param  Type  Description 

event  string 
the event used to originally register a handler 
handler  function 
the handler originally registered 
graph.addNewVertex(key, [value])
Add a new vertex to this graph.
Param  Type  Description 

key  string 
the key with which to refer to this new vertex 
[value]  * 
the value to store in this new vertex 
Throws:
VertexExistsError
if a vertex with this key already exists
graph.setVertex(key, [value])
Set the value of an existing vertex in this graph.
Param  Type  Description 

key  string 
the key belonging to the vertex 
[value]  * 
the value to store in this vertex 
Throws:
VertexNotExistsError
if a vertex with this key does not exist
graph.ensureVertex(key, [value])
Make sure a vertex with a specific key exists in this graph. If it already exists, do nothing. If it does not yet exist, add a new vertex with the given value.
Param  Type  Description 

key  string 
the key for the vertex 
[value]  * 
the value to store if a new vertex is added 
graph.addVertex(key, [value])
Add a new vertex to this graph. If a vertex with this key already exists, the value of that vertex is overwritten.
Param  Type  Description 

key  string 
the key with which to refer to this new vertex 
[value]  * 
the value to store in this new vertex 
graph.removeExistingVertex(key)
Remove an existing vertex from this graph.
Param  Type  Description 

key  string 
the key of the vertex to remove 
Throws:
VertexNotExistsError
if a vertex with this key does not existHasConnectedEdgesError
if there are still edges connected to this vertex
graph.destroyExistingVertex(key)
Remove an existing vertex from this graph, as well as all edges connected to it.
Param  Type  Description 

key  string 
the key of the vertex to remove 
Throws:
VertexNotExistsError
if a vertex with this key does not exist
graph.removeVertex(key)
Remove an existing vertex from this graph. If a vertex with this key does not exist, nothing happens.
Param  Type  Description 

key  string 
the key of the vertex to remove 
Throws:
HasConnectedEdgesError
if there are still edges connected to this vertex
graph.destroyVertex(key)
Remove a vertex from this graph, as well as all edges connected to it. If a vertex with this key does not exist, nothing happens.
Param  Type  Description 

key  string 
the key of the vertex to remove 
graph.vertexCount() ⇒ number
Returns: number
 the number of vertices in the whole graph
graph.hasVertex(key) ⇒ boolean
Ask whether a vertex with a given key exists.
Param  Type  Description 

key  string 
the key to query 
Returns: boolean
 whether there is a vertex with the given key
graph.vertexValue(key) ⇒ *
Get the value associated with the vertex of a given key.
Param  Type  Description 

key  string 
the key to query 
Returns: *
 the value associated with the vertex of the given key. Note that a return value of undefined
can mean
 that there is no such vertex, or
 that the stored value is actually
undefined
.
Use hasVertex to distinguish these cases.
graph.addNewEdge(from, to, [value])
Add a new edge to this graph.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
[value]  * 
the value to store in this new edge 
Throws:
EdgeExistsError
if an edge betweenfrom
andto
already existsVertexNotExistsError
if thefrom
and/orto
vertices do not yet exist in the graph
graph.createNewEdge(from, to, [value])
Add a new edge to this graph. If the from
and/or to
vertices do not yet exist in the graph, they are implicitly added with an undefined
value.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
[value]  * 
the value to store in this new edge 
Throws:
EdgeExistsError
if an edge betweenfrom
andto
already exists
graph.setEdge(from, to, [value])
Set the value of an existing edge in this graph.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
[value]  * 
the value to store in this edge 
Throws:
EdgeNotExistsError
if an edge betweenfrom
andto
does not yet exist
graph.spanEdge(from, to, [value])
Make sure an edge between the from
and to
vertices in this graph. If one already exists, nothing is done. If one does not yet exist, a new edge is added with the given value.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
[value]  * 
the value to store if a new edge is added 
Throws:
VertexNotExistsError
if thefrom
and/orto
vertices do not yet exist in the graph
graph.addEdge(from, to, [value])
Add a new edge to this graph. If an edge between from
and to
already exists, the value of that edge is overwritten.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
[value]  * 
the value to store in this new edge 
Throws:
VertexNotExistsError
if thefrom
and/orto
vertices do not yet exist in the graph
graph.ensureEdge(from, to, [value])
Make sure an edge between the from
and to
vertices exists in this graph. If it already exists, nothing is done. If it does not yet exist, a new edge is added with the given value. If the from
and/or to
vertices do not yet exist in the graph, they are implicitly added with an undefined
value.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
[value]  * 
the value to store if a new edge is added 
graph.createEdge(from, to, [value])
Add a new edge to this graph. If an edge between the from
and to
vertices already exists, the value of that edge is overwritten. If the from
and/or to
vertices do not yet exist in the graph, they are implicitly added with an undefined
value.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
[value]  * 
the value to store if a new edge is added 
graph.removeExistingEdge(from, to)
Remove an existing edge from this graph.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
Throws:
EdgeNotExistsError
if an edge between thefrom
andto
vertices doesn't exist
graph.removeEdge(from, to)
Remove an edge from this graph. If an edge between the from
and to
vertices doesn't exist, nothing happens.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
graph.edgeCount() ⇒ number
Returns: number
 the number of edges in the whole graph
graph.hasEdge(from, to) ⇒ boolean
Ask whether an edge between given from
and to
vertices exist.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
Returns: boolean
 whether there is an edge between the given from
and to
vertices
graph.edgeValue(from, to) ⇒ *
Get the value associated with the edge between given from
and to
vertices.
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
Returns: *
 the value associated with the edge between the given from
and to
vertices Note that a return value of undefined
can mean
 that there is no such edge, or
 that the stored value is actually
undefined
.
Use hasEdge to distinguish these cases.
graph.vertices() ⇒ Iterator.<string, *>
Iterate over all vertices of the graph, in no particular order.
Returns: Iterator.<string, *>
 an object conforming to the ES6 iterator protocol
Example
for (var it = graph.vertices(), kv; !(kv = it.next()).done;) { var key = kv.value[0], value = kv.value[1]; // iterates over all vertices of the graph }
Example
// in ECMAScript 6, you can use a for..of loop for (let [key, value] of graph.vertices()) { // iterates over all vertices of the graph }
See: @@iterator
graph.@@iterator() ⇒ Iterator.<string, *>
A Graph object is itself iterable, and serves as a short notation in ECMAScript 6 to iterate over all vertices in the graph, in no particular order.
Returns: Iterator.<string, *>
 an object conforming to the ES6 iterator protocol
Example
for (let [key, value] of graph) { // iterates over all vertices of the graph }
See: vertices
graph.edges() ⇒ Iterator.<string, string, *>
Iterate over all edges of the graph, in no particular order.
Returns: Iterator.<string, string, *>
 an object conforming to the ES6 iterator protocol
Example
for (var it = graph.edges(), kv; !(kv = it.next()).done;) { var from = kv.value[0], to = kv.value[1], value = kv.value[2]; // iterates over all edges of the graph }
Example
// in ECMAScript 6, you can use a for..of loop for (let [from, to, value] of graph.edges()) { // iterates over all vertices of the graph }
graph.verticesFrom(from) ⇒ Iterator.<string, *, *>
Iterate over the outgoing edges of a given vertex in the graph, in no particular order.
Param  Type  Description 

from  string 
the key of the vertex to take the outgoing edges from 
Throws:
VertexNotExistsError
if a vertex with the givenfrom
key does not exist
Returns: Iterator.<string, *, *>
 an object conforming to the ES6 iterator protocol
Example
for (var it = graph.verticesFrom(from), kv; !(kv = it.next()).done;) { var to = kv.value[0], vertexValue = kv.value[1], edgeValue = kv.value[2]; // iterates over all outgoing vertices of the `from` vertex }
Example
// in ECMAScript 6, you can use a for..of loop for (let [to, vertexValue, edgeValue] of graph.verticesFrom(from)) { // iterates over all outgoing edges of the `from` vertex }
graph.verticesTo(to) ⇒ Iterator.<string, *, *>
Iterate over the incoming edges of a given vertex in the graph, in no particular order.
Param  Type  Description 

to  string 
the key of the vertex to take the incoming edges from 
Throws:
VertexNotExistsError
if a vertex with the givento
key does not exist
Returns: Iterator.<string, *, *>
 an object conforming to the ES6 iterator protocol
Example
for (var it = graph.verticesTo(to), kv; !(kv = it.next()).done;) { var from = kv.value[0], vertexValue = kv.value[1], edgeValue = kv.value[2]; // iterates over all outgoing vertices of the `from` vertex }
Example
// in ECMAScript 6, you can use a for..of loop for (let [from, vertexValue, edgeValue] of graph.verticesTo(to)) { // iterates over all incoming edges of the `to` vertex }
graph.verticesWithPathFrom(from) ⇒ Iterator.<string, *>
Iterate over all vertices reachable from a given vertex in the graph, in no particular order.
Param  Type  Description 

from  string 
the key of the vertex to take the reachable vertices from 
Throws:
VertexNotExistsError
if a vertex with the givenfrom
key does not exist
Returns: Iterator.<string, *>
 an object conforming to the ES6 iterator protocol
Example
for (var it = graph.verticesWithPathFrom(from), kv; !(kv = it.next()).done;) { var key = kv.value[0], value = kv.value[1]; // iterates over all vertices reachable from `from` }
Example
// in ECMAScript 6, you can use a for..of loop for (let [key, value] of graph.verticesWithPathFrom(from)) { // iterates over all vertices reachable from `from` }
graph.verticesWithPathTo(to) ⇒ Iterator.<string, *>
Iterate over all vertices from which a given vertex in the graph can be reached, in no particular order.
Param  Type  Description 

to  string 
the key of the vertex to take the reachable vertices from 
Throws:
VertexNotExistsError
if a vertex with the givento
key does not exist
Returns: Iterator.<string, *>
 an object conforming to the ES6 iterator protocol
Example
for (var it = graph.verticesWithPathTo(to), kv; !(kv = it.next()).done;) { var key = kv.value[0], value = kv.value[1]; // iterates over all vertices from which `to` can be reached }
Example
// in ECMAScript 6, you can use a for..of loop for (let [key, value] of graph.verticesWithPathTo(to)) { // iterates over all vertices from which `to` can be reached }
graph.sources() ⇒ Iterator.<string, *>
Iterate over all vertices that have no incoming edges, in no particular order.
Returns: Iterator.<string, *>
 an object conforming to the ES6 iterator protocol
Example
for (var it = graph.sources(), kv; !(kv = it.next()).done;) { var key = kv.value[0], value = kv.value[1]; // iterates over all vertices with no incoming edges }
Example
// in ECMAScript 6, you can use a for..of loop for (let [key, value] of graph.sources()) { // iterates over all vertices with no incoming edges }
graph.sinks() ⇒ Iterator.<string, *>
Iterate over all vertices that have no outgoing edges, in no particular order.
Returns: Iterator.<string, *>
 an object conforming to the ES6 iterator protocol
Example
for (var it = graph.sinks(), kv; !(kv = it.next()).done;) { var key = kv.value[0], value = kv.value[1]; // iterates over all vertices with no outgoing edges }
Example
// in ECMAScript 6, you can use a for..of loop for (let [key, value] of graph.sinks()) { // iterates over all vertices with no outgoing edges }
graph.vertices_topologically() ⇒ Iterator.<string, *>
Iterate over all vertices of the graph in topological order.
Returns: Iterator.<string, *>
 an object conforming to the ES6 iterator protocol
Example
for (var it = graph.vertices_topologically(), kv; !(kv = it.next()).done;) { var key = kv.value[0], value = kv.value[1]; // iterates over all vertices of the graph in topological order }
Example
// in ECMAScript 6, you can use a for..of loop for (let [key, value] of graph.vertices_topologically()) { // iterates over all vertices of the graph in topological order }
graph.clearEdges()
Remove all edges from the graph, but leave the vertices intact.
graph.clear()
Remove all edges and vertices from the graph, putting it back in its initial state.
graph.equals(other, [eqV], [eqE]) ⇒ boolean
Ask whether this
graph and a given other
graph are equal. Two graphs are equal if they have the same vertices and the same edges.
Param  Type  Description 

other  Graph 
the other graph to compare to this one 
[eqV]  function 
a custom equality function for values stored in vertices; defaults to === comparison; The first two arguments are the values to compare. The third is the corresponding key . 
[eqE]  function 
a custom equality function for values stored in edges; defaults to the function given for trV ; The first two arguments are the values to compare. The third and fourth are the from and to keys respectively. 
Returns: boolean
 true
if the two graphs are equal; false
otherwise
graph.cycles() ⇒ Iterator.<Array.<string>>
Iterate over all simple directed cycles in this graph, in no particular order. If you mutate the graph in between iterations, behavior of the iterator becomes unspecified. (So, don't.)
Returns: Iterator.<Array.<string>>
 an object conforming to the ES6 iterator protocol. Each iterated value is an array containing the vertex keys describing the cycle. These arrays will contain each vertex key only once — even the first/last one.
Example
for (var it = graph.cycles(), kv; !(kv = it.next()).done;) { var cycle = kv.value; // iterates over all cycles of the graph }
Example
// in ECMAScript 6, you can use a for..of loop for (let cycle of graph.cycles()) { // iterates over all cycles of the graph }
graph.cycle() ⇒ Array
Find any directed cycle in this graph.
Returns: Array
 an array containing the vertex keys describing the cycle; null
, if there is no cycle; The array will contain each vertex key only once — even the first/last one.
graph.hasCycle() ⇒ boolean
Test whether this graph contains a directed cycle.
Returns: boolean
 whether this graph contains any directed cycle
graph.paths(from, to) ⇒ Iterator.<Array.<string>>
Iterate over all paths between two given keys in this graph, in no particular order. If you mutate the graph in between iterations, behavior of the iterator becomes unspecified. (So, don't.)
Param  Type  Description 

from  string 
the key for the originating vertex 
to  string 
the key for the terminating vertex 
Throws:
VertexNotExistsError
if thefrom
and/orto
vertices do not yet exist in the graph
Returns: Iterator.<Array.<string>>
 an object conforming to the ES6 iterator protocol. Each iterated value is an array containing the vertexkeys describing the path.
Example
for (var it = graph.paths(), kv; !(kv = it.next()).done;) { var path = kv.value; // iterates over all paths between `from` and `to` in the graph }
Example
// in ECMAScript 6, you can use a for..of loop for (let path of graph.paths()) { // iterates over all paths between `from` and `to` in the graph }
graph.path(from, to) ⇒ Array
Find any path between a given pair of keys.
Param  Type  Description 

from  string 
the originating vertex 
to  string 
the terminating vertex 
Throws:
VertexNotExistsError
if thefrom
and/orto
vertices do not yet exist in the graph
Returns: Array
 an array with the keys of the path found between the two vertices, including those two vertices themselves; null
if no such path exists
graph.hasPath(from, to) ⇒ boolean
Test whether there is a directed path between a given pair of keys.
Param  Type  Description 

from  string 
the originating vertex 
to  string 
the terminating vertex 
Throws:
VertexNotExistsError
if thefrom
and/orto
vertices do not yet exist in the graph
Returns: boolean
 whether such a path exists
graph.outDegree(key) ⇒ number
Get the number of edges going out of a given vertex.
Param  Type  Description 

key  string 
the key of the vertex to query 
Throws:
VertexNotExistsError
if a vertex with this key does not exist
Returns: number
 the number of edges going out of the key
vertex
graph.inDegree(key) ⇒ number
Get the number of edges coming into a given vertex.
Param  Type  Description 

key  string 
the key of the vertex to query 
Throws:
VertexNotExistsError
if a vertex with this key does not exist
Returns: number
 the number of edges coming into the key
vertex
graph.degree(key) ⇒ number
Get the number of edges connected to a given vertex.
Param  Type  Description 

key  string 
the key of the vertex to query 
Throws:
VertexNotExistsError
if a vertex with this key does not exist
Returns: number
 the number of edges connected to the key
vertex
graph.mergeIn(other, [mV], [mE])
Merge another graph into this graph.
Param  Type  Description 

other  Graph 
the other graph to merge into this one 
[mV]  function 
a custom merge function for values stored in vertices; defaults to whichever of the two values is not undefined , giving preference to that of the other graph; The first and second arguments are the vertex values of this graph and the other graph respectively. The third is the corresponding key . 
[mE]  function 
a custom merge function for values stored in edges; defaults to whichever of the two values is not undefined , giving preference to that of the other graph; The first and second arguments are the edge values of this graph and the other graph respectively. The third and fourth are the corresponding from and to keys. 
graph.clone([trV], [trE]) ⇒ Graph
Create a clone of this graph.
Param  Type  Description 

[trV]  function 
a custom transformation function for values stored in vertices; defaults to the identity function; The first argument is the value to clone. The second is the corresponding key . 
[trE]  function 
a custom transformation function for values stored in edges; defaults to the function given for trV ; The first argument is the value to clone. The second and third are the from and to keys respectively. 
Returns: Graph
 a clone of this graph
graph.transitiveReduction([trV], [trE]) ⇒ Graph
Create a clone of this graph, but without any transitive edges.
Param  Type  Description 

[trV]  function 
a custom transformation function for values stored in vertices; defaults to the identity function; The first argument is the value to clone. The second is the corresponding key . 
[trE]  function 
a custom transformation function for values stored in edges; defaults to the function given for trV ; The first argument is the value to clone. The second and third are the from and to keys respectively. 
Returns: Graph
 a clone of this graph with all transitive edges removed
graph.contractPaths([isNexus])
This method replaces stretches of nonbranching directed pathway into single edges. More specifically, it identifies all 'nexus' vertices in the graph and preserves them. It then removes all other vertices and all edges from the graph, then inserts edges between nexuses that summarize the connectivity that was there before.
A nexus is any vertex that is not characterized by '1 edge in, 1 edge out'. A custom isNexus
function may be provided to manually select additional vertices that should be preserved as nexus.
Param  Type  Description 

[isNexus]  function 
a predicate for identifying additional vertices that should be treated as nexus; It receives a key and value associated to a vertex and should return true if and only if that vertex should be a nexus. 
Throws:
BranchlessCycleError
if the graph contains a cycle with no branches or nexuses
toJSON() ⇒ string
Serialize this graph into a JSON string. The resulting string can be deserialized with Graph.fromJSON
Returns: string
 a JSON string representation of the current state of this graph
Example
let json = graph1.toJSON(); let graph2 = Graph.fromJSON(json); console.log(graph1.equals(graph2)); // true
See: Graph.fromJSON
fromJSON(json) ⇒ Graph
Deserialize a string returned from .toJSON()
into a new Graph
instance equal to the original.
Param  Type  Description 

json  string 
a string originally returned from .toJSON() 
Returns: Graph
 a graph equal to the original
Example
let json = graph1.toJSON(); let graph2 = Graph.fromJSON(json); console.log(graph1.equals(graph2)); // true
See: Graph#toJSON
"vertexadded"
An event that is triggered just after a vertex is added to this graph. Handlers receive the new vertex [key, value]
as an argument.
See: on, off
"vertexremoved"
An event that is triggered just after a vertex is removed from this graph. Handlers receive the vertex key as an argument.
See: on, off
"vertexmodified"
An event that is triggered after a vertex in this graph is modified. It is also triggered after any "vertexadded" event. Handlers receive the vertex [key, value]
as an argument.
See: on, off
"edgeadded"
An event that is triggered just after an edge is added to this graph. Handlers receive the new edge [[from, to], value]
as an argument.
See: on, off
"edgeremoved"
An event that is triggered just after an edge is removed from this graph. Handlers receive the edge key [from, to]
as an argument.
See: on, off
"edgemodified"
An event that is triggered after an edge in this graph is modified. It is also triggered after any "edgeadded" event. Handlers receive the edge [[from, to], value]
as an argument.
See: on, off
Graph.VertexExistsError ⇐ Error
This type of error is thrown when specific vertices are expected not to exist, but do.
Extends: Error
vertexExistsError.vertices : Set.<Array>
the set of relevant vertices as [key, value]
shaped arrays
Graph.VertexNotExistsError ⇐ Error
This type of error is thrown when specific vertices are expected to exist, but don't.
Extends: Error
vertexNotExistsError.vertices : Set.<string>
the set of relevant vertex keys
Graph.EdgeExistsError ⇐ Error
This type of error is thrown when specific edges are expected not to exist, but do.
Extends: Error
edgeExistsError.edges : Set.<Array>
the set of relevant edges as [[from, to], value]
shaped arrays
Graph.EdgeNotExistsError ⇐ Error
This type of error is thrown when specific edges are expected to exist, but don't.
Extends: Error
edgeNotExistsError.edges : Set.<Array.<string>>
the set of relevant edge keys as [from, to]
shaped arrays
Graph.HasConnectedEdgesError ⇐ EdgeExistsError
This type of error is thrown when a vertex is expected not to have any connected edges, but does.
Extends: EdgeExistsError
hasConnectedEdgesError.vertex : string
the key of the vertex that has connected edges
hasConnectedEdgesError.edges : Set.<Array>
the set of relevant edges as [[from, to], value]
shaped arrays
Graph.CycleError ⇐ Error
This type of error is thrown when a graph is expected not to have a directed cycle, but does.
Extends: Error
cycleError.cycle : Array.<string>
the vertices involved in the cycle, in order but with an unspecified starting point
Graph.BranchlessCycleError ⇐ CycleError
This type of error is thrown when a graph is expected not to have a branchless directed cycle, but does.
Extends: CycleError
branchlessCycleError.cycle : Array.<string>
the vertices involved in the cycle, in order but with an unspecified starting point