Many classes have shortcut names used when creating (instantiating) a class with a
configuration object. The shortcut name is referred to as an alias
(or xtype
if the
class extends Ext.Component). The alias/xtype is listed next to the class name of
applicable classes for quick reference.
Framework classes or their members may be specified as private
or protected
. Else,
the class / member is public
. Public
, protected
, and private
are access
descriptors used to convey how and when the class or class member should be used.
Public classes and class members are available for use by any other class or application code and may be relied upon as a stable and persistent within major product versions. Public classes and members may safely be extended via a subclass.
Protected class members are stable public
members intended to be used by the
owning class or its subclasses. Protected members may safely be extended via a subclass.
Private classes and class members are used internally by the framework and are not intended to be used by application developers. Private classes and members may change or be omitted from the framework at any time without notice and should not be relied upon in application logic.
static
label next to the
method name. *See Static below.Below is an example class member that we can disect to show the syntax of a class member (the lookupComponent method as viewed from the Ext.button.Button class in this case).
Let's look at each part of the member row:
lookupComponent
in this example)( item )
in this example)Ext.Component
in this case). This may be omitted for methods that do not
return anything other than undefined
or may display as multiple possible values
separated by a forward slash /
signifying that what is returned may depend on the
results of the method call (i.e. a method may return a Component if a get method calls is
successful or false
if unsuccessful which would be displayed as
Ext.Component/Boolean
).PROTECTED
in
this example - see the Flags section below)Ext.container.Container
in this example). The source
class will be displayed as a blue link if the member originates from the current class
and gray if it is inherited from an ancestor or mixed-in class.view source
in the example)item : Object
in the example).undefined
a "Returns" section
will note the type of class or object returned and a description (Ext.Component
in the
example)Available since 3.4.0
- not pictured in
the example) just after the member descriptionDefaults to: false
)The API documentation uses a number of flags to further commnicate the class member's function and intent. The label may be represented by a text label, an abbreviation, or an icon.
classInstance.method1().method2().etc();
false
is returned from
an event handler- Indicates a framework class
- A singleton framework class. *See the singleton flag for more information
- A component-type framework class (any class within the Ext JS framework that extends Ext.Component)
- Indicates that the class, member, or guide is new in the currently viewed version
- Indicates a class member of type config
- Indicates a class member of type property
- Indicates a class member of type
method
- Indicates a class member of type event
- Indicates a class member of type
theme variable
- Indicates a class member of type
theme mixin
- Indicates that the class, member, or guide is new in the currently viewed version
Just below the class name on an API doc page is a row of buttons corresponding to the types of members owned by the current class. Each button shows a count of members by type (this count is updated as filters are applied). Clicking the button will navigate you to that member section. Hovering over the member-type button will reveal a popup menu of all members of that type for quick navigation.
Getting and setter methods that correlate to a class config option will show up in the methods section as well as in the configs section of both the API doc and the member-type menus just beneath the config they work with. The getter and setter method documentation will be found in the config row for easy reference.
Your page history is kept in localstorage and displayed (using the available real estate) just below the top title bar. By default, the only search results shown are the pages matching the product / version you're currently viewing. You can expand what is displayed by clicking on the button on the right-hand side of the history bar and choosing the "All" radio option. This will show all recent pages in the history bar for all products / versions.
Within the history config menu you will also see a listing of your recent page visits. The results are filtered by the "Current Product / Version" and "All" radio options. Clicking on the button will clear the history bar as well as the history kept in local storage.
If "All" is selected in the history config menu the checkbox option for "Show product details in the history bar" will be enabled. When checked, the product/version for each historic page will show alongside the page name in the history bar. Hovering the cursor over the page names in the history bar will also show the product/version as a tooltip.
Both API docs and guides can be searched for using the search field at the top of the page.
On API doc pages there is also a filter input field that filters the member rows using the filter string. In addition to filtering by string you can filter the class members by access level, inheritance, and read only. This is done using the checkboxes at the top of the page.
The checkbox at the bottom of the API class navigation tree filters the class list to include or exclude private classes.
Clicking on an empty search field will show your last 10 searches for quick navigation.
Each API doc page (with the exception of Javascript primitives pages) has a menu view of metadata relating to that class. This metadata view will have one or more of the following:
Ext.button.Button
class has an alternate class name of Ext.Button
). Alternate class
names are commonly maintained for backward compatibility.Runnable examples (Fiddles) are expanded on a page by default. You can collapse and expand example code blocks individually using the arrow on the top-left of the code block. You can also toggle the collapse state of all examples using the toggle button on the top-right of the page. The toggle-all state will be remembered between page loads.
Class members are collapsed on a page by default. You can expand and collapse members using the arrow icon on the left of the member row or globally using the expand / collapse all toggle button top-right.
Viewing the docs on narrower screens or browsers will result in a view optimized for a smaller form factor. The primary differences between the desktop and "mobile" view are:
The class source can be viewed by clicking on the class name at the top of an API doc page. The source for class members can be viewed by clicking on the "view source" link on the right-hand side of the member row.
DragDropManager is a singleton that tracks the element interaction for all DragDrop items in the window. Generally, you will not call this class directly, but it does have helper methods that could be useful in your DragDrop implementations.
The value true
causes config
values to be stored on instances using a
property name prefixed with an underscore ("_") character. A value of false
stores config
values as properties using their exact name (no prefix).
Defaults to:
true
Available since: 5.0.0
The value true
instructs the initConfig
method to only honor values for
properties declared in the config
block of a class. When false
, properties
that are not declared in a config
block will be placed on the instance.
Defaults to:
true
Available since: 5.0.0
Setting this property to false
will prevent nulling object references
on a Class instance after destruction. Setting this to "async"
will delay
the clearing for approx 50ms.
Defaults to:
true
Available since: 6.2.0
Setting this property to true
will result in setting the object's
prototype to null
after the destruction sequence is fully completed.
After that, most attempts at calling methods on the object instance
will result in "method not defined" exception. This can be very helpful
with tracking down otherwise hard to find bugs like runaway Ajax requests,
timed functions not cleared on destruction, etc.
Note that this option can only work in browsers that support Object.setPrototypeOf
method, and is only available in debugging mode.
Defaults to:
false
Available since: 6.2.0
The number of pixels that the mouse needs to move after the mousedown before the drag is initiated. Default=8; defaults to the same value used in the LongPress gesture so that drag cannot be initiated if there is a possible pending longpress
Defaults to:
8
This property is set to true
after the destroy
method is called.
Defaults to:
false
Class to add to the dragged element of a DragDrop instance.
Defaults to:
Ext.baseCSSPrefix + 'dd-drag-current'
Flag that indicates that either the drag pixel threshold or the mousdown time threshold has been met
Defaults to:
false
Array of element ids defined as drag handles. Used to determine if the element that generated the mousedown event is actually the handle and not the html element itself.
Defaults to:
{}
Two dimensional Array of registered DragDrop objects. The first dimension is the DragDrop item group, the second the DragDrop object.
Defaults to:
{}
Internal flag that is set to true when drag and drop has been intialized
Defaults to:
false
In intersect mode, drag and drop interaction is defined by the overlap of two or more drag and drop objects.
Defaults to:
1
This property is set to true
during the call to initConfig
.
Defaults to:
false
Available since: 5.0.0
This property is set to true
if this instance is the first of its class.
Defaults to:
false
Available since: 5.0.0
This value is true
and is used to identify plain objects from instances of
a defined class.
Defaults to:
true
Location cache that is set for all drag drop objects when a drag is initiated, cleared when the drag is finished.
Defaults to:
{}
This config is only provided to provide old, usually unwanted drag/drop behaviour.
From ExtJS 4.1.0 onwards, when drop targets are contained in floating, absolutely positioned elements
such as in Ext.window.Window, which may overlap each other, over
and drop
events
are only delivered to the topmost drop target at the mouse position.
If all targets below that in zIndex order should also receive notifications, set
notifyOccluded
to true
.
Defaults to:
false
In point mode, drag and drop interaction is defined by the location of the cursor during the drag/drop
Defaults to:
0
true
to invoke preventDefault()
on all events during a drag (may be
mouse, touch, or pointer events depending on the platform).
Defaults to:
true
Deprecated since version 6.2.0
Use touchAction or
setTouchAction to prevent specific
default actions during drag
Get the reference to the current class from which this object was instantiated. Unlike Ext.Base#statics,
this.self
is scope-dependent and it's meant to be used for dynamic inheritance. See Ext.Base#statics
for a detailed comparison
Ext.define('My.Cat', {
statics: {
speciesName: 'Cat' // My.Cat.speciesName = 'Cat'
},
constructor: function() {
alert(this.self.speciesName); // dependent on 'this'
},
clone: function() {
return new this.self();
}
});
Ext.define('My.SnowLeopard', {
extend: 'My.Cat',
statics: {
speciesName: 'Snow Leopard' // My.SnowLeopard.speciesName = 'Snow Leopard'
}
});
var cat = new My.Cat(); // alerts 'Cat'
var snowLeopard = new My.SnowLeopard(); // alerts 'Snow Leopard'
var clone = snowLeopard.clone();
alert(Ext.getClassName(clone)); // alerts 'My.SnowLeopard'
Defaults to:
Base
The X position of the mousedown event stored for later use when a drag threshold is met.
Defaults to:
0
The Y position of the mousedown event stored for later use when a drag threshold is met.
Defaults to:
0
true
to invoke stopPropagation()
on all events during a drag (may be
mouse, touch, or pointer events depending on the platform).
Defaults to:
false
Runs method on all drag and drop objects
sMethod : Object
args : Object
Unregisters a drag and drop item. This is executed in DragDrop.unreg, use that method instead of calling this directly.
oDD : Object
clearGroup : Object
This method applies a versioned, deprecation declaration to this class. This
is typically called by the deprecated
config.
deprecations : Object
Utility method to pass to Ext.Array#sort when sorting potential drop targets by z-index.
d1 : Object
d2 : Object
Call the original method that was previously overridden with Ext.Base#override
Ext.define('My.Cat', {
constructor: function() {
alert("I'm a cat!");
}
});
My.Cat.override({
constructor: function() {
alert("I'm going to be a cat!");
this.callOverridden();
alert("Meeeeoooowwww");
}
});
var kitty = new My.Cat(); // alerts "I'm going to be a cat!"
// alerts "I'm a cat!"
// alerts "Meeeeoooowwww"
args : Array/Arguments
The arguments, either an array or the arguments
object
from the current method, for example: this.callOverridden(arguments)
Returns the result of calling the overridden method
Deprecated since version 4.1.0
Use method-callParent instead.
Call the "parent" method of the current method. That is the method previously overridden by derivation or by an override (see Ext#define).
Ext.define('My.Base', {
constructor: function (x) {
this.x = x;
},
statics: {
method: function (x) {
return x;
}
}
});
Ext.define('My.Derived', {
extend: 'My.Base',
constructor: function () {
this.callParent([21]);
}
});
var obj = new My.Derived();
alert(obj.x); // alerts 21
This can be used with an override as follows:
Ext.define('My.DerivedOverride', {
override: 'My.Derived',
constructor: function (x) {
this.callParent([x*2]); // calls original My.Derived constructor
}
});
var obj = new My.Derived();
alert(obj.x); // now alerts 42
This also works with static and private methods.
Ext.define('My.Derived2', {
extend: 'My.Base',
// privates: {
statics: {
method: function (x) {
return this.callParent([x*2]); // calls My.Base.method
}
}
});
alert(My.Base.method(10)); // alerts 10
alert(My.Derived2.method(10)); // alerts 20
Lastly, it also works with overridden static methods.
Ext.define('My.Derived2Override', {
override: 'My.Derived2',
// privates: {
statics: {
method: function (x) {
return this.callParent([x*2]); // calls My.Derived2.method
}
}
});
alert(My.Derived2.method(10); // now alerts 40
To override a method and replace it and also call the superclass method, use method-callSuper. This is often done to patch a method to fix a bug.
args : Array/Arguments
The arguments, either an array or the arguments
object
from the current method, for example: this.callParent(arguments)
Returns the result of calling the parent method
This method is used by an override to call the superclass method but bypass any overridden method. This is often done to "patch" a method that contains a bug but for whatever reason cannot be fixed directly.
Consider:
Ext.define('Ext.some.Class', {
method: function () {
console.log('Good');
}
});
Ext.define('Ext.some.DerivedClass', {
extend: 'Ext.some.Class',
method: function () {
console.log('Bad');
// ... logic but with a bug ...
this.callParent();
}
});
To patch the bug in Ext.some.DerivedClass.method
, the typical solution is to create an
override:
Ext.define('App.patches.DerivedClass', {
override: 'Ext.some.DerivedClass',
method: function () {
console.log('Fixed');
// ... logic but with bug fixed ...
this.callSuper();
}
});
The patch method cannot use method-callParent to call the superclass
method
since that would call the overridden method containing the bug. In
other words, the above patch would only produce "Fixed" then "Good" in the
console log, whereas, using callParent
would produce "Fixed" then "Bad"
then "Good".
args : Array/Arguments
The arguments, either an array or the arguments
object
from the current method, for example: this.callSuper(arguments)
Returns the result of calling the superclass method
This method is called to cleanup an object and its resources. After calling this method, the object should not be used any further in any way, including access to its methods and properties.
To prevent potential memory leaks, all object references will be nulled
at the end of destruction sequence, unless clearPropertiesOnDestroy
is set to false
.
Wrap Ext.Element.fromPagePoint.
This is because in RTL mode we need to reverse any RTLification of the X coordinate because document.elementFromPoint uses LTR.
x : Object
y : Object
Iterates over all of the DragDrop elements to find ones we are hovering over or dropping on
e : Event
the event
isDrop : Boolean
is this a drop op or a mouseover op?
Helper function for getting the best match from the list of drag and drop objects returned by the drag and drop events when we are in INTERSECT mode. It returns either the first object that the cursor is over, or the object that has the greatest overlap with the dragged element.
dds : Ext.dd.DragDrop[]
The array of drag and drop objects targeted
The best single match
Returns a specified config property value. If the name parameter is not passed, all current configuration options will be returned as key value pairs.
name : String (optional)
The name of the config property to get.
peek : Boolean (optional)
true
to peek at the raw value without calling the getter.
Defaults to: false
The config property value.
Returns the style property for the DOM element (i.e., document.getElById(id).style)
id : String
the id of the elment to get
The style property of the element
Returns the DragDrop instance for a given id
id : String
the id of the DragDrop object
the drag drop object, null if it is not found
Get the wrapper for the DOM element specified
id : String
the id of the element to get
the wrapped element
Deprecated
This wrapper isn't that useful
Returns the actual DOM element
id : String
the id of the elment to get
The element
Deprecated
use Ext.lib.Ext.getDom instead
Returns the initial configuration passed to the constructor when instantiating this class.
Given this example Ext.button.Button definition and instance:
Ext.define('MyApp.view.Button', {
extend: 'Ext.button.Button',
xtype: 'mybutton',
scale: 'large',
enableToggle: true
});
var btn = Ext.create({
xtype: 'mybutton',
renderTo: Ext.getBody(),
text: 'Test Button'
});
Calling btn.getInitialConfig()
would return an object including the config
options passed to the create
method:
xtype: 'mybutton',
renderTo: // The document body itself
text: 'Test Button'
Calling btn.getInitialConfig('text')
returns 'Test Button'.
name : String (optional)
Name of the config option to return.
The full config object or a single config value
when name
parameter specified.
Returns a Region object containing the drag and drop element's position and size, including the padding configured for it
oDD : Ext.dd.DragDrop
the drag and drop object to get the location for.
a Region object representing the total area the element occupies, including any padding the instance is configured for.
Returns the drag and drop instances that are in all groups the passed in instance belongs to.
p_oDD : Ext.dd.DragDrop
the obj to get related data for
bTargetsOnly : Boolean
if true, only return targetable objs
the related instances
Collects the z-index of the passed element, looking up the parentNode axis to find an absolutely positioned ancestor which is able to yield a z-index. If found to be not absolutely positionedm returns -1.
This is used when sorting potential drop targets into z-index order so that only the topmost receives over
and drop
events.
element : Object
The z-index of the element, or of its topmost absolutely positioned ancestor. Returns -1 if the element is not absolutely positioned.
Fired after a registered DragDrop object gets the mousedown event. Sets up the events required to track the object being dragged
e : Event
the event
oDD : Ext.dd.DragDrop
the DragDrop object being dragged
Internal function to handle the mousemove event. Will be invoked from the context of the html element.
TODO: figure out what we can do about mouse events lost when the user drags objects beyond the window boundary. Currently we can detect this in internet explorer by verifying that the mouse is down during the mousemove event. Firefox doesn't give us the button state on the mousemove event.
e : Event
the event
Internal function to handle the mouseup event. Will be invoked from the context of the document.
e : Event
the event
Initialize configuration for this class. a typical example:
Ext.define('My.awesome.Class', {
// The default config
config: {
name: 'Awesome',
isAwesome: true
},
constructor: function(config) {
this.initConfig(config);
}
});
var awesome = new My.awesome.Class({
name: 'Super Awesome'
});
alert(awesome.getName()); // 'Super Awesome'
instanceConfig : Object
this
Utility function to determine if a given element has been registered as a drag drop item.
id : String
the element id to check
true if this element is a DragDrop item, false otherwise
Utility function to determine if a given element has been registered as a drag drop handle for the given Drag Drop object.
id : String
the element id to check
true if this element is a DragDrop handle, false otherwise
Returns true if the specified dd target is a legal target for the specifice drag obj
oDD : Ext.dd.DragDrop
the drag obj
oTargetDD : Ext.dd.DragDrop
the target
true if the target is a legal target for the dd obj
Is drag and drop locked?
True if drag and drop is locked, false otherwise.
Checks the cursor location to see if it over the target
pt : Ext.util.Point
The point to evaluate
oTarget : Ext.dd.DragDrop
the DragDrop object we are inspecting
true if the mouse is over the target
My goal is to be able to transparently determine if an object is typeof DragDrop, and the exact subclass of DragDrop. typeof returns "object", oDD.constructor.toString() always returns "DragDrop" and not the name of the subclass. So for now it just evaluates a well-known variable in DragDrop.
oDD : Object
The object to evaluate
true if typeof oDD = DragDrop
Adds a "destroyable" object to an internal list of objects that will be destroyed
when this instance is destroyed (via destroy
).
name : String
value : Object
The value
passed.
Refreshes the cache of the top-left and bottom-right points of the drag and drop objects in the specified group(s). This is in the format that is stored in the drag and drop instance, so typical usage is:
Ext.dd.DragDropManager.refreshCache(ddinstance.groups);
Alternatively:
Ext.dd.DragDropManager.refreshCache({group1:true, group2:true});
TODO: this really should be an indexed array. Alternatively this method could accept both.
groups : Object
an associative array of groups to refresh
Each DragDrop instance must be registered with the DragDropManager. This is executed in DragDrop.init()
oDD : Ext.dd.DragDrop
the DragDrop object to register
sGroup : String
the name of the group this element belongs to
Each DragDrop handle element must be registered. This is done automatically when executing DragDrop.setHandleElId()
sDDId : String
the DragDrop id this element is a handle for
sHandleId : String
the id of the element that is the drag handle
Removes the supplied dd instance from the supplied group. Executed by DragDrop.removeFromGroup, so don't call this function directly.
oDD : Object
sGroup : Object
Sets a single/multiple configuration options.
name : String/Object
The name of the property to set, or a set of key value pairs to set.
value : Object (optional)
The value to set for the name parameter.
this
Fired when either the drag pixel threshold or the mousedown hold time threshold has been met.
x : Number
the X position of the original mousedown
y : Number
the Y position of the original mousedown
Get the reference to the class from which this object was instantiated. Note that unlike Ext.Base#self,
this.statics()
is scope-independent and it always returns the class from which it was called, regardless of what
this
points to during run-time
Ext.define('My.Cat', {
statics: {
totalCreated: 0,
speciesName: 'Cat' // My.Cat.speciesName = 'Cat'
},
constructor: function() {
var statics = this.statics();
alert(statics.speciesName); // always equals to 'Cat' no matter what 'this' refers to
// equivalent to: My.Cat.speciesName
alert(this.self.speciesName); // dependent on 'this'
statics.totalCreated++;
},
clone: function() {
var cloned = new this.self(); // dependent on 'this'
cloned.groupName = this.statics().speciesName; // equivalent to: My.Cat.speciesName
return cloned;
}
});
Ext.define('My.SnowLeopard', {
extend: 'My.Cat',
statics: {
speciesName: 'Snow Leopard' // My.SnowLeopard.speciesName = 'Snow Leopard'
},
constructor: function() {
this.callParent();
}
});
var cat = new My.Cat(); // alerts 'Cat', then alerts 'Cat'
var snowLeopard = new My.SnowLeopard(); // alerts 'Cat', then alerts 'Snow Leopard'
var clone = snowLeopard.clone();
alert(Ext.getClassName(clone)); // alerts 'My.SnowLeopard'
alert(clone.groupName); // alerts 'Cat'
alert(My.Cat.totalCreated); // alerts 3
Internal function to clean up event handlers after the drag operation is complete
e : Event
the event
Utility to stop event propagation and event default, if these features are turned on.
e : Event
the event as returned by this.getEvent()
Destroys a given set of linked
objects. This is only needed if
the linked object is being destroyed before this instance.
names : String[]
The names of the linked objects to destroy.
this
This checks to make sure an element exists and is in the DOM. The main purpose is to handle cases where innerHTML is used to remove drag and drop objects from the DOM.
el : HTMLElement
the element to check
true if the element looks usable
Adds new config properties to this class. This is called for classes when they are declared, then for any mixins that class may define and finally for any overrides defined that target the class.
config : Object
mixinClass : Ext.Class (optional)
The mixin class if the configs are from a mixin.
Add methods / properties to the prototype of this class.
Ext.define('My.awesome.Cat', {
constructor: function() {
...
}
});
My.awesome.Cat.addMembers({
meow: function() {
alert('Meowww...');
}
});
var kitty = new My.awesome.Cat();
kitty.meow();
members : Object
The members to add to this class.
isStatic : Boolean (optional)
Pass true
if the members are static.
Defaults to: false
privacy : Boolean (optional)
Pass true
if the members are private. This
only has meaning in debug mode and only for methods.
Defaults to: false
Add / override static properties of this class.
Ext.define('My.cool.Class', {
...
});
My.cool.Class.addStatics({
someProperty: 'someValue', // My.cool.Class.someProperty = 'someValue'
method1: function() { ... }, // My.cool.Class.method1 = function() { ... };
method2: function() { ... } // My.cool.Class.method2 = function() { ... };
});
members : Object
this
Borrow another class' members to the prototype of this class.
Ext.define('Bank', {
money: '$$$',
printMoney: function() {
alert('$$$$$$$');
}
});
Ext.define('Thief', {
...
});
Thief.borrow(Bank, ['money', 'printMoney']);
var steve = new Thief();
alert(steve.money); // alerts '$$$'
steve.printMoney(); // alerts '$$$$$$$'
fromClass : Ext.Base
The class to borrow members from
members : Array/String
The names of the members to borrow
this
Create a new instance of this Class.
Ext.define('My.cool.Class', {
...
});
My.cool.Class.create({
someConfig: true
});
All parameters are passed to the constructor of the class.
the created instance.
Create aliases for existing prototype methods. Example:
Ext.define('My.cool.Class', {
method1: function() { ... },
method2: function() { ... }
});
var test = new My.cool.Class();
My.cool.Class.createAlias({
method3: 'method1',
method4: 'method2'
});
test.method3(); // test.method1()
My.cool.Class.createAlias('method5', 'method3');
test.method5(); // test.method3() -> test.method1()
alias : String/Object
The new method name, or an object to set multiple aliases. See flexSetter
origin : String/Object
The original method name
Returns the Ext.Configurator
for this class.
Get the current class' name in string format.
Ext.define('My.cool.Class', {
constructor: function() {
alert(this.self.getName()); // alerts 'My.cool.Class'
}
});
My.cool.Class.getName(); // 'My.cool.Class'
className
Used internally by the mixins pre-processor
name : Object
mixinClass : Object
Override members of this class. Overridden methods can be invoked via Ext.Base#callParent.
Ext.define('My.Cat', {
constructor: function() {
alert("I'm a cat!");
}
});
My.Cat.override({
constructor: function() {
alert("I'm going to be a cat!");
this.callParent(arguments);
alert("Meeeeoooowwww");
}
});
var kitty = new My.Cat(); // alerts "I'm going to be a cat!"
// alerts "I'm a cat!"
// alerts "Meeeeoooowwww"
Direct use of this method should be rare. Use Ext.define instead:
Ext.define('My.CatOverride', {
override: 'My.Cat',
constructor: function() {
alert("I'm going to be a cat!");
this.callParent(arguments);
alert("Meeeeoooowwww");
}
});
The above accomplishes the same result but can be managed by the Ext.Loader which can properly order the override and its target class and the build process can determine whether the override is needed based on the required state of the target class (My.Cat).
members : Object
The properties to add to this class. This should be specified as an object literal containing one or more properties.
this class