ImpactStorage - Local Storage plugin for ImpactJS

ImpactStorage is a plugin for HTML5/js game framework ImpactJS, giving developers an easy-to-use interface to localStorage for their projects. Mostly a facade for localStorage, ImpactStorage is set up to bake with your ImpactJS project, take care of some error handling, some convenience methods, as well as support objects in addition to strings.

Created by Jordan Santell for Duck It! (oh god, I need to finish this); enjoy!

Change Log

1.01

• Cleaned up a lot of redundant syntax
• Methods return null if the browser doesn't support localStorage -- isCapable() should still be used
• Added a minified version

Installation

• Move impact-storage.js to your ImpactJS project's plugin folder: [PROJECT]/lib/plugins/impact-storage.js
• Add the plugin to your main.js file

    ig.module(
        'game.main'
    )
    .requires(
        'impact-game',
        ...
        'plugins.impact-storage',
        ...
    )

• Create a local storage object and check out the examples and methods below

    storage: new ig.Storage(),

Methods

• isCapable(): Returns true if the browser is capable of using localStorage. false otherwise.
• isSet(key): Returns true if key has been set in localStorage. false otherwise.
• initUnset(key, value): Iff key has not been set, set key to value
• get(key): Returns the value associated with key in localStorage as a string, or an object if parsable by JSON.
• getInt(key): Returns the value associated with key in localStorage as an int.
• getFloat(key): Returns the value associated with key in localStorage as a float.
• getBool(key): Returns the value associated with key in localStorage as a bool. Returns null if value is not 0, 1, false or true.
• key(n): Returns the value of the key stored at position n in localStorage.
• set(key, value): Sets an item in localStorage with the key value pair. Overwrites the previous value of key if it existed previously. value is stored as either a string or an object.
• setHighest(key, value): Sets an item in localStorage with the key value pair iff the currently stored value is smaller, then returns true. Otherwise returns false.
• remove(key): Removes the item with the specified key.
• clear(): Clears all localStorage data associated with this origin.

Examples

High Score

    this.storage = new ig.Storage();

    // Initialize high score as 0 if 'highScore' does not exist
    this.storage.initUnset('highScore', 0);

During the update loop that determines whether or not the current score should override the score in localStorage:

    var player = this.getEntitiesByType(EntityPlayer)[0];
    /*
       Updates the value of 'highScore' if and only
       if player.score > this.storage.get('highScore')
    */
    this.storage.setHighest('highScore',player.score);

Storing JSON Objects

localStorage stores all data as strings, but the ImpactStorage .set(key, value) and .get(key) methods convert objects to and from strings in order to be saved to localStorage.

    this.storage = new ig.Storage();
    /*
       Player's velocity is an object stored as
       vel: {x: 200, y: 100}
       And that data is now being stored with key playerVel in localStorage
    */
    var player = this.getEntitiesByType(EntityPlayer)[0];
    this.storage.set('playerVel',player.vel)

    // And let's output it for fun
    alert("Player's x velocity: "+this.storage.get('playerVel').x);
    alert("Player's y velocity: "+this.storage.get('playerVel').y);

More Information