Ext.js interview questions

var   json  =  Ext . decode ( response . responseText ); Ext . Msg . alert (‘ Error ’,  json . error );

app . Ajax . request ({    url      :   'db/Contacts' ,    method :   'POST' ,    params :   record . getData (),    scope    :   this ,    success :   function ( response ){        if ( response . success ){            record . id  =  response . id ;            var   store  =  this . getDataview (). getStore ();            store . add ( record );            store . commitChanges ();        }    } });

Ext . define ( 'Ext.form.Basic' , {    ...    updateRecord :  function ( record ) {        var   fields  =  record . fields ,            values  =  this . getFieldValues (),            name ,             obj  = {};        fields . each ( function ( f ) {            name  =  f . name ;            if  ( name   in   values ) {                obj [ name ] =  values [ name ];            }        });     ...

It represents a collection of a set of key and value pairs. Each key in the HashMap must be unique, the same key cannot exist twice. Access to items is provided via the key only.  Sample usage: var map = new Ext.util.HashMap(); map.add('key1', 1); map.add('key2', 2); map.add('key3', 3); map.each(function(key, value, length){     console.log(key, value, length); }); The HashMap is an unordered class, there is no guarantee when iterating over the items that they will be in any particular order. If this is required, then use a Ext.util.MixedCollection.

To create a singleton class,just set to true, the class will be instantiated as singleton. For example: Ext.define('Logger', {     singleton: true,     log: function(msg) {         console.log(msg);     } }); Logger.log('Hello');

The constructors are special method that are executed when a class is instantiated. You can use constructor to prepare the object in any way required. For example, to set up the default property values. eg: Ext.define('Test.Emp', {    config: {         name: 'Raja',         gender: 'Male'    },    constructor: function(config){        // initialize our config object        this.initConfig(config);     },     getDetails: function(){       alert('My name is ' + this.name);     } }); var honey = Ext.create("Test.Emp",{ name: 'Mary',        gender: 'Female' });