Ext.util.DelayedTask

Hierarchy

Ext.Base
Ext.util.DelayedTask

Files

The DelayedTask class provides a convenient way to "buffer" the execution of a method, performing setTimeout where a new timeout cancels the old timeout. When called, the task will wait the specified time period before executing. If during that time period, the task is called again, the original call will be canceled. This continues so that the function is only called a single time for each iteration.

This method is especially useful for things like detecting whether a user has finished typing in a text field. An example would be performing validation on a keypress. You can use this class to buffer the keypress events for a certain number of milliseconds, and perform only if they stop for that amount of time.

Using Ext.util.DelayedTask is very simple:

//create the delayed task instance with our callback
var task = Ext.create('Ext.util.DelayedTask', {
     fn: function() {
        console.log('callback!');
     }
});

task.delay(1500); //the callback function will now be called after 1500ms

task.cancel(); //the callback function will never be called now, unless we call delay() again

Example

//create a textfield where we can listen to text
var field = Ext.create('Ext.field.Text', {
    xtype: 'textfield',
    label: 'Length: 0'
});

//add the textfield into a fieldset
Ext.Viewport.add({
    xtype: 'formpanel',
    items: [{
        xtype: 'fieldset',
        items: [field],
        instructions: 'Type into the field and watch the count go up after 500ms.'
    }]
});

//create our delayed task with a function that returns the fields length as the fields label
var task = Ext.create('Ext.util.DelayedTask', function() {
    field.setLabel('Length: ' + field.getValue().length);
});

// Wait 500ms before calling our function. If the user presses another key
// during that 500ms, it will be canceled and we'll wait another 500ms.
field.on('keyup', function() {
    task.delay(500);
});
Defined By

Config options

Ext.util.DelayedTask
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: Objectprivate
Ext.util.DelayedTask
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: Objectprivate
Ext.util.DelayedTask
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: Objectprivate
Ext.util.DelayedTask
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: Objectprivate
Ext.util.DelayedTask
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: Objectprivate

Properties

Defined By

Instance properties

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); // 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'
Defined By

Static properties

...

Defaults to: []

Methods

Defined By

Instance methods

Ext.util.DelayedTask
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new( fn, scope, args ) : Ext.util.DelayedTask
The parameters to this constructor serve as defaults and are not required. ...

The parameters to this constructor serve as defaults and are not required.

Parameters

  • fn : Function

    The default function to call.

  • scope : Object

    The default scope (The this reference) in which the function is called. If not specified, this will refer to the browser window.

  • args : Array

    The default Array of arguments.

Returns

Ext.util.DelayedTask
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( config )private
Changes the value into an array if it isn't one. ...

Changes the value into an array if it isn't one.

Parameters

Call the original method that was previously overridden with override, This method is deprecated as callParent does ...

Call the original method that was previously overridden with override,

This method is deprecated as callParent does the same thing.

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"

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

To override a method and replace it and also call the superclass method, use callSuper. This is often done to patch a method to fix a bug.

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

This method is used by an override to call the superclass method but bypass any overridden 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', {
     method: function () {
         console.log('Bad');

         // ... logic but with a bug ...

         this.callParent();
     }
 });

To patch the bug in DerivedClass.method, the typical solution is to create an override:

 Ext.define('App.paches.DerivedClass', {
     override: 'Ext.some.DerivedClass',

     method: function () {
         console.log('Fixed');

         // ... logic but with bug fixed ...

         this.callSuper();
     }
 });

The patch method cannot use 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".

Parameters

  • args : Array/Arguments

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

Returns

  • Object

    Returns the result of calling the superclass method

Ext.util.DelayedTask
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( )
Cancel the last queued timeout ...

Cancel the last queued timeout

Fires

    Ext.util.DelayedTask
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    ( delay, newFn, newScope, newArgs )
    Cancels any pending timeout and queues a new one. ...

    Cancels any pending timeout and queues a new one.

    Parameters

    • delay : Number

      The milliseconds to delay

    • newFn : Function

      Overrides the original function passed when instantiated.

    • newScope : Object

      Overrides the original scope passed when instantiated. Remember that if no scope is specified, this will refer to the browser window.

    • newArgs : Array

      Overrides the original args passed when instantiated.

    Fires

      Ext.util.DelayedTask
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      ( ) : Object
      Returns the value of args. ...

      Returns the value of args.

      Returns

      ...

      Parameters

      Ext.util.DelayedTask
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      ( ) : Object
      Returns the value of delay. ...

      Returns the value of delay.

      Returns

      Ext.util.DelayedTask
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      ( ) : Object
      Returns the value of fn. ...

      Returns the value of fn.

      Returns

      Returns the initial configuration passed to constructor. ...

      Returns the initial configuration passed to constructor.

      Parameters

      • name : String (optional)

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

      Returns

      Ext.util.DelayedTask
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      ( ) : Object
      Returns the value of interval. ...

      Returns the value of interval.

      Returns

      Ext.util.DelayedTask
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      ( ) : Object
      Returns the value of scope. ...

      Returns the value of scope.

      Returns

      ...

      Parameters

      ( 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'
      

      Parameters

      Returns

      • Object

        mixins The mixin prototypes as key - value pairs

      Fires

        ( names, callback, scope )private
        ...

        Parameters

        Ext.util.DelayedTask
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        ( args )
        Sets the value of args. ...

        Sets the value of args.

        Parameters

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

        Parameters

        Returns

        Ext.util.DelayedTask
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        ( delay )
        Sets the value of delay. ...

        Sets the value of delay.

        Parameters

        Ext.util.DelayedTask
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        ( fn )
        Sets the value of fn. ...

        Sets the value of fn.

        Parameters

        Ext.util.DelayedTask
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        ( interval )
        Sets the value of interval. ...

        Sets the value of interval.

        Parameters

        Ext.util.DelayedTask
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        ( scope )
        Sets the value of scope. ...

        Sets the value of scope.

        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
        

        Returns

        Ext.util.DelayedTask
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        ( newInterval, oldInterval )private
        Clears the old interval ...

        Clears the old interval

        Parameters

        Defined By

        Static methods

        ( config, fullMerge )privatestatic
        ...

        Parameters

        ( members )chainableprivatestatic
        ...

        Parameters

        ( name, member )chainableprivatestatic
        ...

        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.addMembers({
             meow: function() {
                alert('Meowww...');
             }
         });
        
         var kitty = new My.awesome.Cat();
         kitty.meow();
        

        Parameters

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

        Add / override static properties of this class.

        Ext.define('My.cool.Class', {
            // this.se
        });
        
        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() { ... };
        });
        

        Parameters

        Returns

        ( xtype )chainableprivatestatic
        ...

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

        Parameters

        • fromClass : Ext.Base

          The class to borrow members from

        • members : Array/String

          The names of the members to borrow

        Returns

        ( args )protectedstatic
        ...

        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.

        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()
        

        Parameters

        ( parent )privatestatic
        ...

        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'
        

        Returns

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

        Used internally by the mixins pre-processor

        Parameters

        ( fn, scope )chainableprivatestatic
        ...

        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 2.1, 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).

        This method has been deprecated since 2.1.0

        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