dijkstra

A minor re-write of albertorestifo/node-dijkstra with a more limited API.

Installation

yarn add smart-parks/dijkstra

Usage

Basic example:

const Graph = require('dijkstra')

const route = new Graph()

route.connect('A', 'B', 1)
route.connect('B', 'A', 1)
route.connect('B', 'C', 2)
route.connect('B', 'D', 4)
route.connect('C', 'B', 2)
route.connect('C', 'D', 1)
route.connect('D', 'C', 1)
route.connect('D', 'B', 4)

route.path('A', 'D') // => [ 'A', 'B', 'C', 'D' ]

API

Graph([nodes])

Parameters

• Object optional: Initial nodes graph.

A nodes graph must follow this structure:

{
  node: {
    neighbor: cost Number
  }
}

{
  'A': {
    'B': 1
  },
  'B': {
    'A': 1,
    'C': 2,
    'D': 4
  }
}

Example

const route = new Graph()

// or with pre-populated graph
const route = new Graph({
  'A': { 'B': 1 },
  'B': { 'A': 1, 'C': 2, 'D': 4 }
})

Graph#connect(from, to, cost)

Adds a connection to the graph.

const a = { name: 'Billy' } // any value
const b = { name: 'Sam' } // any value

const route = new Graph()

route.connect(a, b, 100)

Graph#removeNode(node)

Removes a node and all its references from the graph

Parameters

• node: name of the node to remove

Graph#path(start, goal [, options])

Parameters

• start: starting node
• goal: goal node
• Object options optional: Addittional options:
  • Boolean trim, default false: If set to true, the result won't include the start and goal nodes
  • Boolean reverse, default false: If set to true, the result will be in reverse order, from goal to start
  • Boolean cost, default false: If set to true, an object will be returned with the following keys:
    • Array path: Computed path (subject to other options)
    • Number cost: Total cost for the found path
  • Array avoid, default []: Nodes to be avoided

Returns

If options.cost is false (default behaviour) an Array will be returned, containing the name of the crossed nodes. By default it will be ordered from start to goal, and those nodes will also be included. This behaviour can be changes with options.trim and options.reverse (see above)

If options.cost is true, an Object with keys path and cost will be returned. path follows the same rules as above and cost is the total cost of the found route between nodes.

When to route can be found, the path will be set to null.