SafeObject.js v1.2.3

SafeObject.js

SafeObject is a class to manage your instance properties. When the object is constructed, SafeObject initialize all registered properties to null.

How-To

npm install SafeObject.js
bower install SafeObject.js

Inherit/Include SafeObject

First, you need to include or extend your class/function with SafeObject (Notice the constructor property is required)

// Inheritance
function View() {
  SafeObject.call(this);
  this.el = document.createElement('div');
}
View.prototype = Object.create(SafeObject.prototype, {
  constructor: {
    value: View,
    enumerable: false
  }
});

// Inclusion
function View(options) {
  Backbone.View.call(this, options);
  SafeObject.include(this);
}

View.prototype = Object.create(Backbone.View.prototype, {
  constructor: {
    value: View,
    enumerable: false
  }
});

Define instance properties

In all cases, you can define instance properties with several ways. The SafeObject.PropertyDescriptor is the same as native property descriptor:

{
  value: any,
  enumerable: boolean,
  writable: boolean,
  configurable: boolean
}

When you write a property descriptor with mutable objects like {} or [] or Date, you should use a function wrapper. If you dont, you'll define the same mutable object in all instances of this object.

The new thing here is the last argument:

// by default, this is a factory
new PropertyDescriptor(function () {return [];})
// but if you won't, you must give the last argument (isFactory) explicitly to false
new PropertyDescriptor(function () {return this.data.map(function (id) { return d.id; }); }, true, true, true, false);

View.INSTANCE_PROPERTIES = {
  // will be initialize to (value: null, enumerable: true, writable: true, configurable: true, factory: false)
  request: null,
  // will be initialize to (value: false, enumerable: true, writable: true, configurable: true, factory: false)
  isRendered: false,
  // will be initialize to (value: '', enumerable: false, writable: true, configurable: false, factory: false)
  text: new SafeObject.PropertyDescriptor('', false, true, false),
  // will be initialize to (value: function, enumerable: true, writable: true, configurable: true, factory: true)
  childViews: function () { return []; },
  _isRequired: true,
  // will be initialize to (value: function, enumerable: false, writable: true, configurable: false, factory: false)
  isRequired: new SafeObject.PropertyDescriptor(function () { return this._isRequired; }, false, true, false, false) ],

  // or if your complex values dont need any arguments
  childViews: Array,
  attributes: Object
};

Now your instance should look like this:

var view = new View();
view.request === null;
view.isRendered === false;
view.text === '';
Array.isArray(view.childViews) && view.childViews.length === 0;
view._isRequired === true;
view.isRequired() === true;

And when you dont need it anymore, calling destroy method will set all registered fields to null

view.destroy();
// all fields will be equal to null
view.request === null;
view.isRendered === null;
view.text === null;
view.childViews === null;
view._isRequired === null;
view.isRequired === null;

Define custom Constructor

If you tried to use a custom class like a Native element like Array or Date, this shouldn't work.

class Vector3 {
  constructor(x, y, z) {
    this.x = x | 0;
    this.y = y | 0;
    this.z = z | 0;
  }
}
class Entity {}
Entity.INSTANCE_PROPERTIES = {
  speed: Vector3
};

You must define this Class as registered to SafeObject

SafeObject.registerConstructor(Vector3);