AStar-Typescript

The A* search algorithm library in TypeScript

AStar-TypeScript is an A* pathfinding API written in TypeScript to use for your HTML5 games or other browser-based projects.

This library was influenced and inspired by @qioa - PathFinding.js, @bgrins - javascript-astar, @prettymuchbryce - easystarjs and @redblobgames.

Buy me a coffee

Whether you use this project, have learned something from it, or just like it, please consider supporting it by buying me a coffee.

Live example

Select a folder, navigate to it, and clone this repository with this command-line:

git clone https://github.com/digitsensitive/astar-typescript.git

Install the dependencies:

yarn install

Run the live example:

yarn run-example

Installation

yarn add astar-typescript
npm install astar-typescript --save
bower install astar-typescript --save

Import

TypeScript

import { AStarFinder } from "astar-typescript";

Javascript

let AStarFinder = require("astar-typescript");

AMD

define(function(require,exports,module){
  let AStarFinder = require('astar-typescript');
});

Basic Usage

Create an astar instance:

private aStarInstance: AStarFinder;

Load grid data:

Using an array (hardcoded or from a Tilemap-Editor)

0 = walkable 1 = not walkable

let myMatrix = [
  [0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 1],
  [0, 0, 1, 1, 0, 1, 1, 0],
  [0, 0, 1, 0, 0, 0, 1, 0],
  [0, 0, 0, 0, 0, 0, 1, 0],
  [1, 1, 1, 0, 1, 0, 1, 0],
  [0, 0, 0, 0, 1, 0, 1, 0],
  [0, 0, 1, 0, 0, 0, 0, 0]
];

this.aStarInstance = new AStarFinder({
  grid: {
    matrix: myMatrix
  }
});

or randomly generated array from width and height

this.aStarInstance = new AStarFinder({
  grid: {
    width: 8,
    height: 8
  }
});

Get the path:

let startPos = { x: 0, y: 0 };
let goalPos = { x: 4, y: 5 };

let myPathway = this.aStarInstance.findPath(startPos, goalPos);

Advanced Usage

Additional parameters may be passed to adapt your finder.

If you want to disable diagonal movements:

this.aStarInstance = new AStarFinder({
  grid: {
    width: 8,
    height: 8
  },
  diagonalAllowed: false
});

Set the heuristic function (Manhattan, Euclidean, Chebyshev or Octile):

this.aStarInstance = new AStarFinder({
  grid: {
    width: 8,
    height: 8
  },
  heuristic: "Manhattan"
});

Set a maxCost for each grid node to enable using cost in the pathfinding calculation allowing you to make nodes less preferable.

0 = walkable 2 = walkable but not prefered 5 = not walkable

let myMatrix = [
  [0, 0, 2, 2, 2, 2, 0, 0],
  [0, 0, 2, 2, 2, 2, 0, 5],
  [0, 0, 5, 5, 0, 5, 5, 0],
  [0, 0, 5, 0, 0, 0, 5, 0],
  [0, 0, 0, 0, 0, 0, 5, 0],
  [5, 5, 5, 0, 5, 0, 5, 0],
  [0, 0, 0, 0, 5, 0, 5, 0],
  [0, 0, 5, 0, 0, 0, 0, 0]
];

this.aStarInstance = new AStarFinder({
  grid: {
    matrix: myMatrix,
    maxCost: 5,
  }
});

It is possible to adjust the weight of the heuristic function. For example if you use 0, every heuristic function will return zero. That is how you can turn A* into Dijkstra’s Algorithm. Depending on the weight value you can decide if you prefer speed or accuracy. The lower the weight is, the lower will the heuristic function get, which will make the A* slower.

this.aStarInstance = new AStarFinder({
  grid: {
    width: 8,
    height: 8
  },
  weight: 0.7
});

Include or Exclude the start and end node:

this.aStarInstance = new AStarFinder({
  grid: {
    width: 8,
    height: 8
  },
  includeStartNode: true,
  includeEndNode: true
});

Prettier

This library uses Prettier. The configuration used can be seen in the .prettierrc file. More informations about the format options can be found here.

License

MIT License

Copyright (c) 2017 - 2020 digitsensitive [email protected]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.