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https://github.com/prettymuchbryce/easystarjs

An asynchronous A* pathfinding API written in Javascript.
https://github.com/prettymuchbryce/easystarjs

astar asynchronous easystar game grid javascript pathfinding

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An asynchronous A* pathfinding API written in Javascript.

Lists

README 

        
[](http://easystarjs.com/)



#### HTML5/Javascript Pathfinding Library #####



[Click here for a demonstration](http://easystarjs.com/)



## Installation

* **Web:** Find the minified file in the __/bin__ directory

* **node.js:** `npm install easystarjs`

* **Phaser:** see [Phaser Plugin](https://github.com/appsbu-de/phaser_plugin_pathfinding)

* **Bower:** `bower install easystarjs`



## Description 

easystar.js is an asynchronous A* pathfinding API written in Javascript for use in your HTML5 games and interactive projects. The goal of this project is to make it easy and fast to implement performance conscious pathfinding. 



## Features



* Calculates asynchronously for better overall performance

* Simple API

* Small. ~7kb

* Use it with any existing Javascript Framework

* TypeScript support



## API



#### Main Methods



```javascript

var easystar = new EasyStar.js();

```

```javascript

easystar.setGrid(twoDimensionalArray);

```

```javascript

easystar.setAcceptableTiles(arrayOfAcceptableTiles);

```

```javascript

easystar.findPath(startX, startY, endX, endY, callback);

```

```javascript

easystar.calculate();

```



#### Additional Features



```javascript

easystar.setIterationsPerCalculation(someValue);

```

```javascript

easystar.avoidAdditionalPoint(x, y);

```

```javascript

easystar.enableDiagonals();

```

```javascript

easystar.enableCornerCutting();

```

```javascript

easystar.setAdditionalPointCost(x, y, cost);

```

```javascript

easystar.setTileCost(tileType, multiplicativeCost);

```

```javascript

easystar.enableSync();

```

```javascript

easystar.setDirectionalCondition(x, y, [EasyStar.TOP, EasyStar.LEFT]); // only accessible from the top and left

```

```javascript

var instanceId = easystar.findPath(startX, startY, endX, endY, callback);

// ...

easystar.cancelPath(instanceId);

```



## Usage



First create EasyStar.

```javascript

// for web

var easystar = new EasyStar.js();



// for node.js

var easystarjs = require('easystarjs');

var easystar = new easystarjs.js();

```



Create a grid, or tilemap. You may have made this with a level editor, or procedurally. Let's keep it simple for this example.

```javascript

var grid = [[0,0,1,0,0],

            [0,0,1,0,0],

            [0,0,1,0,0],

            [0,0,1,0,0],

            [0,0,0,0,0]];

```



Set our grid.

```javascript	

easystar.setGrid(grid);

```

Set tiles which are "walkable".

```javascript

easystar.setAcceptableTiles([0]);

```



Find a path.

```javascript

easystar.findPath(0, 0, 4, 0, function( path ) {

	if (path === null) {

		alert("Path was not found.");

	} else {

		alert("Path was found. The first Point is " + path[0].x + " " + path[0].y);

	}

});

```



EasyStar will not yet start calculating my path. 



In order for EasyStar to actually start calculating, I must call the calculate() method.



You should call `easystar.calculate()` on a ticker, or setInterval.



If you have a large grid, then it is possible that these calculations could slow down the browser. 

For this reason, it might be a good idea to give EasyStar a smaller `iterationsPerCalculation` value via 



```javascript

easystar.setIterationsPerCalculation(1000);

```



It may take longer for you to find a path this way, but you won't completely halt your game trying to find one.

The only thing left to do now is to calculate the path.



```javascript

easystar.calculate();

```



## License



easystar.js is licensed under the MIT license. You may use it for commercial use.



## Running the demo locally



In order to run the demo you will need node.js, and npm installed.



```sh

git clone https://github.com/prettymuchbryce/easystarjs.git



cd easystarjs/demo



npm install



node app.js

```



Open your browser to 127.0.0.1:3000 to see the example.



## Testing



`npm run test`



## Support



If you have any questions, comments, or suggestions please open an issue.