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Ext.data.Field

Hierarchy

Ext.Base
Ext.data.Field

Requires

Files

Fields are used to define what a Model is. They aren't instantiated directly - instead, when we create a class that extends Ext.data.Model, it will automatically create a Field instance for each field configured in a Model. For example, we might set up a model like this:

Ext.define('User', {
    extend: 'Ext.data.Model',
    config: {
        fields: [
            'name', 'email',
            {name: 'age', type: 'int'},
            {name: 'gender', type: 'string', defaultValue: 'Unknown'}
        ]
    }
});

Four fields will have been created for the User Model - name, email, age and gender. Note that we specified a couple of different formats here; if we only pass in the string name of the field (as with name and email), the field is set up with the 'auto' type. It's as if we'd done this instead:

Ext.define('User', {
    extend: 'Ext.data.Model',
    config: {
        fields: [
            {name: 'name', type: 'auto'},
            {name: 'email', type: 'auto'},
            {name: 'age', type: 'int'},
            {name: 'gender', type: 'string', defaultValue: 'Unknown'}
        ]
    }
});

Types and conversion

The type is important - it's used to automatically convert data passed to the field into the correct format. In our example above, the name and email fields used the 'auto' type and will just accept anything that is passed into them. The 'age' field had an 'int' type however, so if we passed 25.4 this would be rounded to 25.

Sometimes a simple type isn't enough, or we want to perform some processing when we load a Field's data. We can do this using a convert function. Here, we're going to create a new field based on another:

Ext.define('User', {
    extend: 'Ext.data.Model',
    config: {
        fields: [
            'name', 'email',
            {name: 'age', type: 'int'},
            {name: 'gender', type: 'string', defaultValue: 'Unknown'},

            {
                name: 'firstName',
                convert: function(value, record) {
                    var fullName  = record.get('name'),
                        splits    = fullName.split(" "),
                        firstName = splits[0];

                    return firstName;
                }
            }
        ]
    }
});

Now when we create a new User, the firstName is populated automatically based on the name:

var ed = Ext.create('User', {name: 'Ed Spencer'});

console.log(ed.get('firstName')); //logs 'Ed', based on our convert function

In fact, if we log out all of the data inside ed, we'll see this:

console.log(ed.data);

//outputs this:
{
    age: 0,
    email: "",
    firstName: "Ed",
    gender: "Unknown",
    name: "Ed Spencer"
}

The age field has been given a default of zero because we made it an int type. As an auto field, email has defaulted to an empty string. When we registered the User model we set gender's defaultValue to 'Unknown' so we see that now. Let's correct that and satisfy ourselves that the types work as we expect:

ed.set('gender', 'Male');
ed.get('gender'); //returns 'Male'

ed.set('age', 25.4);
ed.get('age'); //returns 25 - we wanted an int, not a float, so no decimal places allowed

Available since: 1.1.0

Defined By

Config options

Ext.data.Field
view source
: Booleanprivate
Used for validating a model. ...

Used for validating a model. Defaults to true. An empty value here will cause Ext.data.Model.isValid to evaluate to false.

Defaults to: true

Available since: 1.1.0

Use when converting received data into a boolean, string or number type (either int or float). ...

Use when converting received data into a boolean, string or number type (either int or float). If the value cannot be parsed, null will be used if allowNull is true, otherwise the value will be 0. Defaults to true.

Defaults to: true

Available since: 2.0.0

Ext.data.Field
view source
: Stringprivate
...

Defaults to: 'action'

Available since: 2.0.1

A function which converts the value provided by the Reader into an object that will be stored in the Model. ...

A function which converts the value provided by the Reader into an object that will be stored in the Model. It is passed the following parameters:

  • v : Mixed

    The data value as read by the Reader, if undefined will use the configured defaultValue.

  • rec : Ext.data.Model

    The data object containing the Model as read so far by the Reader. Note that the Model may not be fully populated at this point as the fields are read in the order that they are defined in your fields array.

Example of convert functions:

function fullName(v, record) {
    return record.name.last + ', ' + record.name.first;
}

function location(v, record) {
    return !record.city ? '' : (record.city + ', ' + record.state);
}

Ext.define('Dude', {
    extend: 'Ext.data.Model',
    fields: [
        {name: 'fullname',  convert: fullName},
        {name: 'firstname', mapping: 'name.first'},
        {name: 'lastname',  mapping: 'name.last'},
        {name: 'city', defaultValue: 'homeless'},
        'state',
        {name: 'location',  convert: location}
    ]
});

// create the data store
var store = Ext.create('Ext.data.Store', {
    reader: {
        type: 'json',
        model: 'Dude',
        idProperty: 'key',
        rootProperty: 'daRoot',
        totalProperty: 'total'
    }
});

var myData = [
    { key: 1,
      name: { first: 'Fat',    last:  'Albert' }
      // notice no city, state provided in data2 object
    },
    { key: 2,
      name: { first: 'Barney', last:  'Rubble' },
      city: 'Bedrock', state: 'Stoneridge'
    },
    { key: 3,
      name: { first: 'Cliff',  last:  'Claven' },
      city: 'Boston',  state: 'MA'
    }
];

Available since: 1.1.0

Used when converting received data into a Date when the type is specified as "date". ...

Used when converting received data into a Date when the type is specified as "date".

A format string for the Ext.Date.parse function, or "timestamp" if the value provided by the Reader is a UNIX timestamp, or "time" if the value provided by the Reader is a javascript millisecond timestamp. See Ext.Date.

Available since: 1.1.0

Ext.data.Field
view source
: Objectprivate

Available since: 2.0.0

The default value used when a Model is being created by a Reader when the item referenced by the mapping does not exi...

The default value used when a Model is being created by a Reader when the item referenced by the mapping does not exist in the data object (i.e. undefined). Defaults to "".

Available since: 1.1.0

Ext.data.Field
view source
: Objectprivate

Used in LocalStorage stuff

Used in LocalStorage stuff

Available since: 2.0.0

(Optional) A path expression for use by the Ext.data.reader.Reader implementation that is creating the Model to extra...

(Optional) A path expression for use by the Ext.data.reader.Reader implementation that is creating the Model to extract the Field value from the data object. If the path expression is the same as the field name, the mapping may be omitted.

The form of the mapping expression depends on the Reader being used.

  • Ext.data.reader.Json

    The mapping is a string containing the javascript expression to reference the data from an element of the data2 item's rootProperty Array. Defaults to the field name.

  • Ext.data.reader.Xml

    The mapping is an Ext.DomQuery path to the data item relative to the DOM element that represents the record. Defaults to the field name.

  • Ext.data.reader.Array

    The mapping is a number indicating the Array index of the field's value. Defaults to the field specification's Array position.

If a more complex value extraction strategy is required, then configure the Field with a convert function. This is passed the whole row object, and may interrogate it in whatever way is necessary in order to return the desired data.

Available since: 1.1.0

Ext.data.Field
view source
: String
The name by which the field is referenced within the Model. ...

The name by which the field is referenced within the Model. This is referenced by, for example, the dataIndex property in column definition objects passed to Ext.grid.property.HeaderContainer.

Note: In the simplest case, if no properties other than name are required, a field definition may consist of just a String for the field name.

Available since: 1.1.0

Ext.data.Field
view source
: Boolean
False to exclude this field from being synchronized with the server or localstorage. ...

False to exclude this field from being synchronized with the server or localstorage. This option is useful when model fields are used to keep state on the client but do not need to be persisted to the server. Defaults to true.

Defaults to: true

Available since: 2.0.0

Ext.data.Field
view source
: String
Initial direction to sort ("ASC" or "DESC"). ...

Initial direction to sort ("ASC" or "DESC"). Defaults to "ASC".

Defaults to: "ASC"

Available since: 1.1.0

A function which converts a Field's value to a comparable value in order to ensure correct sort ordering. ...

A function which converts a Field's value to a comparable value in order to ensure correct sort ordering. Predefined functions are provided in Ext.data.SortTypes. A custom sort example:

// current sort     after sort we want
// +-+------+          +-+------+
// |1|First |          |1|First |
// |2|Last  |          |3|Second|
// |3|Second|          |2|Last  |
// +-+------+          +-+------+

sortType: function(value) {
   switch (value.toLowerCase()) // native toLowerCase():
   {
      case 'first': return 1;
      case 'second': return 2;
      default: return 3;
   }
}

Available since: 1.1.0

Ext.data.Field
view source
: String/Object
The data type for automatic conversion from received data to the stored value if convert has not been specified. ...

The data type for automatic conversion from received data to the stored value if convert has not been specified. This may be specified as a string value. Possible values are

  • auto (Default, implies no conversion)
  • string
  • int
  • float
  • boolean
  • date

This may also be specified by referencing a member of the Ext.data.Types class.

Developers may create their own application-specific data types by defining new members of the Ext.data.Types class.

Defaults to: 'auto'

Available since: 1.1.0

Ext.data.Field
view source
: Booleandeprecated
Use when converting received data into a boolean, string or number type (either int or float). ...

Use when converting received data into a boolean, string or number type (either int or float). If the value cannot be parsed, null will be used if allowNull is true, otherwise the value will be 0. Defaults to true.

Available since: 1.1.0

This cfg has been deprecated since 2.0.0

Please use allowNull instead.

Properties

Defined By

Instance properties

Ext.data.Field
view source
: Booleanprivate
...

Defaults to: true

Available since: 2.0.0

Get the reference to the current class from which this object was instantiated. ...

Get the reference to the current class from which this object was instantiated. Unlike statics, this.self is scope-dependent and it's meant to be used for dynamic inheritance. See statics for a detailed comparison

Ext.define('My.Cat', {
    statics: {
        speciesName: 'Cat' // My.Cat.speciesName = 'Cat'
    },

    constructor: function() {
        alert(this.self.speciesName); / dependentOL 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'

Available since: 2.0.0

Defined By

Static properties

...

Defaults to: []

Available since: 2.0.0

Methods

Defined By

Instance methods

Ext.data.Field
view source
new( config ) : Ext.data.Field
...

Available since: 1.1.0

Parameters

Returns

Fires

    Ext.data.Field
    view source
    ( convert )private
    ...

    Available since: 2.0.0

    Parameters

    Fires

      Ext.data.Field
      view source
      ( sortType )private
      ...

      Available since: 2.0.0

      Parameters

      Fires

        Ext.data.Field
        view source
        ( type )private
        ...

        Available since: 2.0.0

        Parameters

        Call the original method that was previously overridden with override Ext.define('My.Cat', { constructor: functi...

        Call the original method that was previously overridden with 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!");
        
                var instance = this.callOverridden();
        
                alert("Meeeeoooowwww");
        
                return instance;
            }
        });
        
        var kitty = new My.Cat(); // alerts "I'm going to be a cat!"
                                  // alerts "I'm a cat!"
                                  // alerts "Meeeeoooowwww"
        

        Available since: 2.0.0

        Parameters

        • args : Array/Arguments

          The arguments, either an array or the arguments object from the current method, for example: this.callOverridden(arguments)

        Returns

        • Object

          Returns the result of calling the overridden method

        Call the "parent" method of the current method. ...

        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 methods.

         Ext.define('My.Derived2', {
             extend: 'My.Base',
        
             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',
        
             statics: {
                 method: function (x) {
                     return this.callParent([x*2]); // calls My.Derived2.method
                 }
             }
         });
        
         alert(My.Derived2.method(10); // now alerts 40
        

        Available since: 2.0.0

        Parameters

        • args : Array/Arguments

          The arguments, either an array or the arguments object from the current method, for example: this.callParent(arguments)

        Returns

        • Object

          Returns the result of calling the parent method

        Ext.data.Field
        view source
        ( ) : Booleanprivate
        Returns the value of allowBlank. ...

        Returns the value of allowBlank.

        Available since: 2.0.0

        Returns

        Ext.data.Field
        view source
        ( ) : Boolean
        Returns the value of allowNull. ...

        Returns the value of allowNull.

        Available since: 2.0.0

        Returns

        Returns the value of bubbleEvents. ...

        Returns the value of bubbleEvents.

        Available since: 2.0.1

        Returns

        ...

        Available since: 2.0.0

        Parameters

        Ext.data.Field
        view source
        ( ) : Function
        Returns the value of convert. ...

        Returns the value of convert.

        Available since: 2.0.0

        Returns

        ...

        Available since: 2.0.0

        Ext.data.Field
        view source
        ( ) : String
        Returns the value of dateFormat. ...

        Returns the value of dateFormat.

        Available since: 2.0.0

        Returns

        Ext.data.Field
        view source
        ( ) : Object
        Returns the value of decode. ...

        Returns the value of decode.

        Available since: 2.0.0

        Returns

        Returns the value of defaultValue. ...

        Returns the value of defaultValue.

        Available since: 2.0.0

        Returns

        Ext.data.Field
        view source
        ( ) : Object
        Returns the value of encode. ...

        Returns the value of encode.

        Available since: 2.0.0

        Returns

        Returns the initial configuration passed to constructor. ...

        Returns the initial configuration passed to constructor.

        Available since: 2.0.0

        Parameters

        • name : String (optional)

          When supplied, value for particular configuration option is returned, otherwise the full config object is returned.

        Returns

        Returns the value of mapping. ...

        Returns the value of mapping.

        Available since: 2.0.0

        Returns

        Ext.data.Field
        view source
        ( ) : String
        Returns the value of name. ...

        Returns the value of name.

        Available since: 2.0.0

        Returns

        Ext.data.Field
        view source
        ( ) : Boolean
        Returns the value of persist. ...

        Returns the value of persist.

        Available since: 2.0.0

        Returns

        Ext.data.Field
        view source
        ( ) : String
        Returns the value of sortDir. ...

        Returns the value of sortDir.

        Available since: 2.0.0

        Returns

        Ext.data.Field
        view source
        ( ) : Function
        Returns the value of sortType. ...

        Returns the value of sortType.

        Available since: 2.0.0

        Returns

        Ext.data.Field
        view source
        ( ) : String/Object
        Returns the value of type. ...

        Returns the value of type.

        Available since: 2.0.0

        Returns

        ...

        Available since: 2.0.0

        Parameters

        Ext.data.Field
        view source
        ( )private
        ...

        Available since: 2.0.0

        ( instanceConfig ) : Objectchainableprotected
        Initialize configuration for this class. ...

        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'
        

        Available since: 2.0.0

        Parameters

        Returns

        • Object

          mixins The mixin prototypes as key - value pairs

        Fires

          ( names, callback, scope )private
          ...

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( allowBlank )private
          Sets the value of allowBlank. ...

          Sets the value of allowBlank.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( allowNull )
          Sets the value of allowNull. ...

          Sets the value of allowNull.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( bubbleEvents )
          Sets the value of bubbleEvents. ...

          Sets the value of bubbleEvents.

          Available since: 2.0.1

          Parameters

          ( config, applyIfNotSet ) : Ext.Basechainableprivate
          ...

          Available since: 2.0.0

          Parameters

          Returns

          Ext.data.Field
          view source
          ( convert )
          Sets the value of convert. ...

          Sets the value of convert.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( dateFormat )
          Sets the value of dateFormat. ...

          Sets the value of dateFormat.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( decode )
          Sets the value of decode. ...

          Sets the value of decode.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( defaultValue )
          Sets the value of defaultValue. ...

          Sets the value of defaultValue.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( encode )
          Sets the value of encode. ...

          Sets the value of encode.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( mapping )
          Sets the value of mapping. ...

          Sets the value of mapping.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( name )
          Sets the value of name. ...

          Sets the value of name.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( persist )
          Sets the value of persist. ...

          Sets the value of persist.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( sortDir )
          Sets the value of sortDir. ...

          Sets the value of sortDir.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( sortType )
          Sets the value of sortType. ...

          Sets the value of sortType.

          Available since: 2.0.0

          Parameters

          Ext.data.Field
          view source
          ( type )
          Sets the value of type. ...

          Sets the value of type.

          Available since: 2.0.0

          Parameters

          Get the reference to the class from which this object was instantiated. ...

          Get the reference to the class from which this object was instantiated. Note that unlike 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
          

          Available since: 2.0.0

          Returns

          Ext.data.Field
          view source
          ( newType, oldType )private
          ...

          Available since: 2.0.0

          Parameters

          Fires

            Defined By

            Static methods

            ( config, fullMerge )privatestatic
            ...

            Available since: 2.0.0

            Parameters

            ( members )chainableprivatestatic
            ...

            Available since: 2.0.0

            Parameters

            ( name, member )chainableprivatestatic
            ...

            Available since: 2.0.0

            Parameters

            ( members )chainablestatic
            Add methods / properties to the prototype of this class. ...

            Add methods / properties to the prototype of this class.

            Ext.define('My.awesome.Cat', {
                constructor: function() {
                    ...
                }
            });
            
             My.awesome.Cat.implement({
                 meow: function() {
                    alert('Meowww...');
                 }
             });
            
             var kitty = new My.awesome.Cat;
             kitty.meow();
            

            Available since: 2.0.0

            Parameters

            ( members ) : Ext.Basechainablestatic
            Add / override static properties of this class. ...

            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() { ... };
            });
            

            Available since: 2.0.0

            Parameters

            Returns

            ( xtype )chainableprivatestatic
            ...

            Available since: 2.0.0

            Parameters

            ( fromClass, members ) : Ext.Basechainableprivatestatic
            Borrow another class' members to the prototype of this class. ...

            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 '$$$'
            steve.printMoney(); // alerts '$$$$$$$'
            

            Available since: 2.0.0

            Parameters

            • fromClass : Ext.Base

              The class to borrow members from

            • members : Array/String

              The names of the members to borrow

            Returns

            ( args )privatestatic
            ...

            Available since: 2.0.0

            Parameters

            Create a new instance of this Class. ...

            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.

            Available since: 2.0.0

            Returns

            ( alias, origin )static
            Create aliases for existing prototype methods. ...

            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()
            

            Available since: 2.0.0

            Parameters

            ( parent )privatestatic
            ...

            Available since: 2.0.0

            Parameters

            Get the current class' name in string format. ...

            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'
            

            Available since: 2.0.0

            Returns

            ...

            Available since: 2.0.0

            ( name, mixinClass )privatestatic
            Used internally by the mixins pre-processor ...

            Used internally by the mixins pre-processor

            Available since: 2.0.0

            Parameters

            ( fn, scope )chainableprivatestatic
            ...

            Available since: 2.0.0

            Parameters

            ( members ) : Ext.Basechainabledeprecatedstatic
            Override members of this class. ...

            Override members of this class. Overridden methods can be invoked via 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!");
            
                    var instance = this.callParent(arguments);
            
                    alert("Meeeeoooowwww");
            
                    return instance;
                }
            });
            
            var kitty = new My.Cat(); // alerts "I'm going to be a cat!"
                                      // alerts "I'm a cat!"
                                      // alerts "Meeeeoooowwww"
            

            As of 4.1, direct use of this method is deprecated. Use Ext.define instead:

            Ext.define('My.CatOverride', {
                override: 'My.Cat',
                constructor: function() {
                    alert("I'm going to be a cat!");
            
                    var instance = this.callParent(arguments);
            
                    alert("Meeeeoooowwww");
            
                    return instance;
                }
            });
            

            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).

            Available since: 2.0.0

            This method has been deprecated since 4.1.0

            Please use Ext.define instead

            Parameters

            • members : Object

              The properties to add to this class. This should be specified as an object literal containing one or more properties.

            Returns

            ...

            Available since: 2.0.0