See a demo at http://www.briangrinstead.com/files/astar/
If you want just the A* search code (not the demo visualization), use code like this http://gist.github.com/581352
<script type='text/javascript' src='astar.js'></script> <script type='text/javascript'> var graph = new Graph([ [1,1,1,1], [0,1,1,0], [0,0,1,1] ]); var start = graph.grid[0][0]; var end = graph.grid[1][2]; var result = astar.search(graph, start, end); // result is an array containing the shortest path var graphDiagonal = new Graph([ [1,1,1,1], [0,1,1,0], [0,0,1,1] ], { diagonal: true }); var start = graphDiagonal.grid[0][0]; var end = graphDiagonal.grid[1][2]; var resultWithDiagonals = astar.search(graphDiagonal, start, end, { heuristic: astar.heuristics.diagonal }); // Weight can easily be added by increasing the values within the graph, and where 0 is infinite (a wall) var graphWithWeight = new Graph([ [1,1,2,30], [0,4,1.3,0], [0,0,5,1] ]); var startWithWeight = graphWithWeight.grid[0][0]; var endWithWeight = graphWithWeight.grid[1][2]; var resultWithWeight = astar.search(graphWithWeight, startWithWeight, endWithWeight); // resultWithWeight is an array containing the shortest path taking into account the weight of a node </script>
A few notes about weight values:
- A weight of 0 denotes a wall.
- A weight cannot be negative.
- A weight cannot be between 0 and 1 (exclusive).
- A weight can contain decimal values (greater than 1).
The original version of the algorithm used a list, and was a bit clearer but much slower. It was based off the original blog post. The code is available at: https://github.com/bgrins/javascript-astar/tree/0.0.1/original-implementation.
The newest version of the algorithm using a Binary Heap. It is quite faster than the original. http://www.briangrinstead.com/blog/astar-search-algorithm-in-javascript-updated Binary Heap taken from http://eloquentjavascript.net/appendix2.html (license: http://creativecommons.org/licenses/by/3.0/)
If you don't have grunt installed, follow the grunt getting started guide first.
Pull down the project, then run:
npm install
grunt