Introduction to ExtJS Interview Questions and Answers
Ext is used to develop UI of the web application; this framework is based on Javascript; it inherits all the features of the JavaScript along with its own features; it is also used to create desktop applications, it provides dual features, All modern web browsers support it like chrome, safari, FF. It is supported in mobile devices also by the product name sencha. The latest version of ext is used for mobile and desktop applications without any difference for the two platforms code; this is the 6th version of it. It is MVC/MVVM based architecture.
Jack Slocum created the first version of Ext Javascript in 2006, which was Ext JS 1.1. It had a set of various utility classes for a various purpose; it was an extension of YUI. It was named as a YUI-ext library.
Ext JS 2.0 version was released in 2007. It had a new many APIs documentation for desktop applications with limited features and functionality. This version doesn’t have backward compatibility with earlier versions of Ext Javascript.
Ext javascript 3.0 version was released in 2009. it brought many new features like charts and list views, but It was not very fast. It had backward compatibility with its previous version, 2.0.
Ext Javascript version 4.0 was released in 2011. This version has a completely revised structure, which was followed by model view controller architecture and brought the speed.
Features of Ext JS
It provides Code compatibility of new versions of EX with the older ones of EX. Customizable UI widgets with a collection of rich UI such as pivot, grids, forms, charts, trees. Customizable Themes Ext Javascript widgets provide many themes that can be used to make our websites more attractive, interactive and these themes always consistent across platforms. It provides a very flexible way for layout management which helps to organize the display of data and content across multiple devices, browsers, and screen sizes. It is protocol less, having the ability to access data from any back-end source.
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Advantages
Offer various types of widgets to make a powerful UI easily. Speed up the teams to create web applications desktop applications with compelling user experience. Sencha has reduced the cost of web application development. Sencha Ext JS is one of the leading standards for business-grade, enterprise-based web application development. It provides various tools, a plugin that is necessary to build robust applications for desktop and tablets.
It provides cross-platform development across tablets, desktops, and smartphones – for both modern any kind of browser as well as legacy any kind of browsers. It can increase development teams’ productivity and maintenance teams by integrating into any type of enterprise development environment via various IDE plugins provided by the sencha.
To start development in Ex javascript application, sencha has provided many tools which can be used at various level like production, debugging level, self-learning level.
Sencha CMD
To do code modification of EX javascript sencha CMD tools provided by Sencha which help to
scaffolding and production build generation.
Sencha Inspector
In Sencha to debug the application while developing, Sencha Inspector is used as a debugging tool that helps a developer to do debugging in a smooth way.
Sencha IDE Plugins
To use an open-source IDE Sencha provides a various plugin which can be plugged to IDE like Intellij, WebstromTo starts the development with these fast IDE in a smooth way it provides features like code compilation, code navigation, code inspection, code refactoring, code generation, template creation, spell-checking, etc.
If you are looking for a job related to ExtJS, you need to prepare for the 2021 ExtJS Interview Questions. Every interview is different from the different job profiles, but still, to clear the interview, you need to have a good and clear knowledge of ExtJS. Here, we have prepared the important ExtJS Interview Questions and Answers, which will help you succeed in your interview.
In this 2021 ExtJS Interview Questions article, we shall present the 10 most important and frequently used ExtJS interview questions. These questions will help students build their concepts around ExtJS and help them ace the interview.
Part 1 – ExtJS Interview Questions (Basic)
This first part covers basic Interview Questions and Answers.
1. what is Ext JS and the name library on which it extended?
Answer:
It is a JavaScript framework to develop rich UI web-based desktop applications. Ext JS stands for extended JavaScript. It is a Sencha product extended from YUI (Yahoo user interface).
2. what is the difference between Ext JS and jQuery?
Answer:
These are the basic ExtJS Interview Questions asked in an interview. Both the frameworks are quite different; we can compare ExtJS and jQuery UI as Ext JS is a full-fledged UI rich framework. But still, Ext JS has many more components then jQuery UI.
3. Explain ViewModel in MVVM architecture?
Answer:
In MVVM architecture controller of MVC is replaced by ViewModel.
ViewModel: − it is responsible for mapping between views and models.
Is it responsible for wrapping of the data from the model to view? It does it without having any interaction with the view of the UI. It has only knowledge of the model.
Let us move to the next ExtJS Interview Questions.
4. What is the use of Ext.onReady()?
Answer:
Ext.onReady() is the first method which is called when the DOM is fully loaded so that whatever element we want to refer will be available when a script runs.
5. Program to write before and after load events in the store?
Answer:
grid.getStore().on ({
beforeload : function(store) {
// do whater operation needed as per requirments
},
load : {
fn : function(store) {
// do whatever operation needed as per requirements
},
scope : this
}
store.load();
});
Part 2 – ExtJS Interview Questions (Advanced)
Let us now have a look at the advanced Interview Questions and Answers.
6. Explain renderer and its use?
Answer:
A renderer is used when we want to manipulate the data which we get from the store to show manipulated data based on some criteria.
It is a column property that can be used as: –
renderer: function(value, metadata, record, rowIndex, colIndex, store){
// logic to perform operation
}
7. What are all the layouts in Ext JS?
Answer:
Different type of layouts is in Ext JS −
Absolute, Accordion, Anchor, Border, Auto, hBox, vBox, Card(TabPanel), Card(Wizard), Column, Fit, Table
8. Explain vType in Ext JS?
Answer:
This is the validation type that can be customized easily. Few vType provided by Ext JS are −
- emailText: − This returns false if a text is not a valid email address.
- alphanumText: − This returns false if the text entered has any symbol other than an alphabetic or numeric value.
9. Explain the latest version of Ext JS and its benefits?
Answer:
The latest version of Ext is version 6th which brought the 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. What are the Ext JS implementation tools?
Answer:
Ext JS can be implemented on any popular integrated development environment (IDE) such as Eclipse, Sublime, Aptana, Westrom, etc.
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