Friday 27 April 2018

Ext Js Interview Questions

1.   What is Ext JS?

Ext JS stands for extended JavaScript. It is a JavaScript framework to develop rich UI web based desktop applications.

2.   Ext JS is extended on which library?

It is a Sencha product which is extended from YUI (Yahoo user interface).

3.   What are the main library files to add in HTML page?

These are the main files to include in HTML page to run Ext JS code −
  • Ext-all.js
  • Ext-all.css

4.   Explain features of Ext JS.

  • Customizable UI widgets with collection of rich UI such as Grids, pivot grids, forms, charts, trees.
  • Code compatibility of new versions with the older one.
  • A flexible layout manager helps to organize the display of data and content across multiple browsers, devices, and screen sizes.
  • Advance data package decouples the UI widgets from the data layer. The data package allows client-side collection of data using highly functional models that enable features such as sorting and filtering.
  • It is protocol agnostic, and can access data from any back-end source.
  • Customizable Themes Ext JS widgets are available in multiple out-of-the-box themes that are consistent across platforms.

5.   Explain advantage of using Ext JS.

·        Streamlines cross-platform development across desktops, tablets, and smartphones — for both modern and legacy browsers.
·        Increases the productivity of development teams by integrating into enterprise development environments via IDE plugins.
·        Reduces the cost of web application development.
·        Empowers teams to create apps with a compelling user experience.
·        It has set of widgets for making UI powerful and easy.
·        It follows MVC architecture so highly readable code.

6.   Explain limitations of using Ext JS.

·        The size of library is large around 500 KB which makes initial loading time more and makes application slow.
·        HTML is full of <DIV> tags makes it complex and difficult to debug.
·        According to general public license policy it is free for open source applications but paid for commercial applications.
·        Some times for loading even simple things requires few lines of coding which is simpler in plain html or Jquery.
·        Need quite experienced developer for developing Ext JS applications.

7.   What are the browser Ext JS supports?

Ext JS supports cross browser compatibility, it supports all major browsers as −
  • IE 6 and above
  • Firefox 3.6 and above
  • Chrome10 and above
  • Safari 4 and above
  • Opera 11 and above

8.   Ext JS supports which architecture?

Ext JS 4+ supports MVC (Model view controller) architecture. From Ext JS 5 it started supporting MVVM (Model View Viewmodel) also.

9.   What is the latest version of Ext JS and its benefits?

Ext JS 6 is the latest version of Ext JS which has major benefit that it can be used for both desktop and as well as mobile applications. Basically it is a merge of Ext JS (desktop applications) and Sencha touch (mobile application).

10.  Advice for the developer who are going to use it for the first time.

Ext JS is a JavaScript framework so to start using it you should use have prior knowledge of HTML and JS (not expert level but should have basic understanding). Then it takes to understand the basic so give it time and learn gradually.

11. Difference between Ext JS and jQuery.

Both the frameworks are quite different we can compare Ext JS and jQuery UI as Ext JS is full-fledged UI rich framework. But still Ext JS has much more components then jQuery UI.

12. Difference between Ext JS and Angular JS.

Parameter
Ext JS
Angular JS
Rich UI
Ext JS provides rich UI options such as forms , grid, charts
Angular JS does not provide rich UI inbuilt
Rich theme UI components
Ext JS provides multiple themes inbuilt
Angular JS does not provide Rich UI it has to be integrated with AngularUI, AngularBootstarp etc.
Cross browser compatibility
Ext JS provide cross browser compatibility it works for almost all the browsers IE6+, FF, Chrome, Safari, Opera etc.
Angular JS has to use third party library such as jQuery, jqLite for solving this purpose.
Automatic testing support
Possible only with external tools
Provides inbuilt.
Two way data binding
In Ext JS 5 two way binding is included.
It supports two way binding start from first version.
Performance
Ext JS is comparatively heavier and slower.
Angular JS is light weight framework than Ext JS
Build tools
Ext JS uses Sencha cmd tool for builds
Angular JS uses third party tools such as grunt.

13.  What do you know about different versions of Ext JS?

Ext JS 1.1
The first version of Ext JS was developed by Jack Slocum in 2006. It was a set of utility classes which is an extension of YUI. He named the library as YUI-ext.
Ext JS 2.0
Ext JS version 2.0 was released in 2007. This version had new API documentation for desktop Application with limited features. This version doesn't had backward compatibility with previous version of Ext JS.
Ext JS 3.0
Ext JS version 3.0 was released in 2009. This version added new features as chart and list view but at the cost of speed. It had backwards compatible with version 2.0.
Ext JS 4.0
After the release of Ext JS 3 the developers of Ext JS had the major challenge of ramping up the speed. Ext JS version 4.0 was released in 2011. It had the complete revised structure which followed by MVC architecture and a speedy application.
Ext JS 5.0
Ext JS version 5.0 was released in 2014. The major change in this release was to change the MVC architecture to MVVM architecture. It includes the ability to build desktop apps on touch-enabled devices, two-way data binding, responsive layouts and many more features.
Ext JS 6.0
Ext JS 6 merges the Ext JS (for desktop application) and sencha touch (for mobile application) framework.

14. What are the different Ext JS components?

Ext JS has various UI components some of the majorly used components are −
  • Grid
  • Form
  • Message Box
  • Progress Bar
  • Tool Tip
  • Window
  • HTML Editor
  • Charts

15. What is xType in Ext JS?

xType defines the type of Ext JS UI component, which is determined during rendering of the component. E.g. textField, Numeric, button etc.

More about ExtJS:

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