graph-route-finder v1.1.0

graph-route-finder

Find all/least-cost routes in weighted directed graph with given limitations. The idea of this lib is to find all possible routes, including the least-cost one, in a weighted directed graph which is commonly used in delivery services. With a bunch of limitations, it can be used in many scenarios. For example, find all possible routes from A to B, while total cost should be less than 20, whole stops should be less than 4.

How to use

Init graph

const Graph = require('graph-route-finder');

const graph = new Graph({
      A: { B: 1, C: 4, D: 10 },
      B: { E: 3 },
      C: { D: 4, F: 2 },
      D: { E: 1 },
      E: { B: 3, A: 2 },
      F: { D: 1 },
    }); 

console.log(graph.nodes)
// {
//   A: { B: 1, C: 4, D: 10 },
//   B: { E: 3 },
//   C: { D: 4, F: 2 },
//   D: { E: 1 },
//   E: { B: 3, A: 2 },
//   F: { D: 1 },
// }

Refresh graph

graph.refresh(nodes)

Which will remove previous nodes and add provided graph nodes to totally refresh graph instance.

graph.refresh({ J: { A: 10 } });

console.log(graph.nodes)
// { J: { A: 10 } }

Get all nodes that start from the given node

graph.from(nodeName)

console.log(graph.from('A'));
// { B: 1, C: 4, D: 10 }

Get all nodes that direct to the given node

graph.to(nodeName)

console.log(graph.to('B'))
// { A: { B: 1 }, E: { B: 3 } }

Add a new route or update a existent route

graph.set(startNode, endNode , cost)

By default, cost will be 1 if not provided.

graph.set('A', 'J', 12);
console.log(graph.nodes);
// {
//   A: { B: 1, C: 4, D: 10, J: 12 },
//   B: { E: 3 },
//   C: { D: 4, F: 2 },
//   D: { E: 1 },
//   E: { B: 3, A: 2 },
//   F: { D: 1 },
// }

graph.set('A', 'B', 12);
console.log(graph.nodes);
// {
//   A: { B: 12, C: 4, D: 10, J: 12 },
//   B: { E: 3 },
//   C: { D: 4, F: 2 },
//   D: { E: 1 },
//   E: { B: 3, A: 2 },
//   F: { D: 1 },
// }

Remove a existent route

graph.remove(startNode, endNode)

Trying to remove a non-existent route will result in no change in graph.

graph.remove('A', 'B');
console.log(graph.nodes);
// {
//   A: { C: 4, D: 10 },
//   B: { E: 3 },
//   C: { D: 4, F: 2 },
//   D: { E: 1 },
//   E: { B: 3, A: 2 },
//   F: { D: 1 },
// }

Calculate cost for given route(a array of nodes)

graph.calculate(nodeName1, nodeName2, ...)

This function will go through each node to the next from given node array to calculate cost for the whole route, if a path is not found in the route, No​ ​Such​ ​Route error will be returned.

graph.calculate(['E', 'A', 'C', 'F'])
// 8

graph.calculate(['A', 'D', 'F']);
// Error { message: 'No​ ​Such​ ​Route }

Find routes for given start node and end node

graph.findRoutes(startNode, endNode , options )

This function will return a list of all possible routes from start node to end node. The list will be sorted by cost ASC.

• Options:
  • routeLimit: Infinity. How many routes to return, by giving routeLimit:1, it will return only one route which is also the least-cost route.
  • stopLimit: Infinity. The maximum stops the routes can reach.
  • costLimit: Infinity. The maximum cost the routes can reach.
  • pathReuseLimit: 1. Experiment How many time the same route can be reused.

const routes = graph.findRoutes('E', 'D', { stopLimit: 4 });
// [
//   {
//     nodes: [ 'E', 'A', 'C', 'F', 'D' ],
//     paths: { 'E-A': 1, 'A-C': 1, 'C-F': 1, 'F-D': 1 },
//     cost: 9
//   },
//   {
//     nodes: [ 'E', 'A', 'C', 'D' ],
//     paths: { 'E-A': 1, 'A-C': 1, 'C-D': 1 },
//     cost: 10
//   },
//   { 
//     nodes: [ 'E', 'A', 'D' ], 
//     paths: { 'E-A': 1, 'A-D': 1 }, 
//     cost: 12 
//   },
//   {
//     nodes: [ 'E', 'B', 'E', 'A', 'D' ],
//     paths: { 'E-B': 1, 'B-E': 1, 'E-A': 1, 'A-D': 1 },
//     cost: 18
//   }
// ]

const routes = graph.findRoutes('E', 'E', { costLimit: 10 });
// [
//   { 
//     nodes: [ 'E', 'B', 'E' ], 
//     paths: { 'E-B': 1, 'B-E': 1 }, 
//     cost: 6 },
//   {
//     nodes: [ 'E', 'A', 'B', 'E' ],
//     paths: { 'E-A': 1, 'A-B': 1, 'B-E': 1 },
//     cost: 6
//   },
//   {
//     nodes: [ 'E', 'A', 'C', 'F', 'D', 'E' ],
//     paths: { 'E-A': 1, 'A-C': 1, 'C-F': 1, 'F-D': 1, 'D-E': 1 },
//     cost: 10
//   }
// ]

const routes = graph.findRoutes('E', 'E', { routeLimit: 1 });
// [
//   { nodes: [ 'E', 'B', 'E' ], paths: { 'E-B': 1, 'B-E': 1 }, cost: 6 }
// ]

How to test

yarn test

License