Creates observable states to an object. States are defined using JSON Schema 03 standard. Object properties are monitored for changes, changes trigger JSON Schema validation tests. When a state is enabled or disabled a notification event is emitted on the object.

Module Methods

• create( config ): Creates new instance of Object States and returns the Object.
• mixin( target ): Adds the prototypal methods of Object States to a target object.
• bind( target, config ): Binds Object States' prototypal methods to a target object with configuration.
• call( target, config ) / apply( target ): Applies Object States to a target object.
• set( key, value ): Set a setting to instance meta. To set default setting use 'defaults' as key.
• get( key ): Get a meta value.
• defineState( target, state ): Define a state for the target object.
• defineStates( target, states ): Define multiple states for a target object.
• validate( target, schema ): Validate target object against a JSON Schema.

Instance Methods

Instance methods are available if the create() method was used to instantiate a new Object State.

• defineState( state ): Define a state for the current instance.
• defineStates( states ): Define multiple states for the current instance.
• validate( schema ): Validate current instance against a schema.
• set( key, value ): Set a setting to instance meta. To set default setting use 'defaults' as key.
• get( key ): Get a meta value.

Basic Usage: With Instantiation

var AbstractObject = require( 'object-state' ).create();

AbstractObject.defineStates({
  active: {
    properties: {
      users: { type: 'number', minimum: 5; }
    }
  }
});

AbstractObject.uses = 3;
AbstractObject.is.active; // -> false
AbstractObject.uses = 6;
AbstractObject.is.active; // -> true

Basic Usage: Without Instantiation

var StateMonitor = {};

require( 'object-state' ).defineStates( StateMonitor, {
  pinged_and_dinged: {
    description: "StateMonitor has been pinged and dinged.",
    properties: {
      ping: { value: true },
      ding: { value: true }
    }
  }
});

StateMonitor.on( 'pinged_and_dinged', function() {
  console.log( "We've been pinged and dinged!" );
});

StateMonitor.ping = true;
StateMonitor.ding = true;

console.log( StateMonitor.is.pinged_and_dinged ) // -> true

Advanced Usage

// Create Express Server    
var app = require( 'express' )();
var server = app.listen( 0 );

// Define states    
require( 'object-state' ).defineStates( server, {
  active: {
    'description': 'The Express server has connections.',
    'properties': {
      '_connections': { type: 'number', minimum: 1 }
    }
  },
  overloaded: {
    'description': 'The Express server has too many connections.',
    'properties': {
      '_connections': { type: 'number', minimum: 3 }
    }
  }
});

// Do somethign when sever has too many connections    
server.on( 'overloaded', function( server, state ) {
  console.log( "Express server is overloaded, there are over %s connections.", state.properties._connections.minimum );
});

License

(The MIT License)

Copyright (c) 2013 Usability Dynamics, Inc. <[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.