What is Ext JS?
Ext JS, developed by Sencha, is a robust and highly popular JavaScript framework used for building dynamic, data-driven web applications. It is especially well-suited for developing complex, enterprise-level applications with a high degree of interactivity. Ext JS provides an extensive range of components such as grids, charts, trees, forms, and much more, all of which can be used to build feature-rich user interfaces.
With its declarative approach to UI design and strong architecture, Ext JS offers developers a structured way to build applications that scale. It provides a comprehensive solution for the UI layer, handling data management, client-side rendering, and a wide range of visual elements. One of its major benefits is its ability to create single-page applications (SPAs) that load only the essential data and elements, resulting in a faster and more seamless user experience.
Ext JS also includes support for cross-browser compatibility, ensuring that applications developed using the framework run seamlessly across major browsers like Chrome, Firefox, Internet Explorer, Safari, and others. Additionally, it comes with extensive documentation, a rich set of UI components, and enterprise-grade features, making it suitable for large-scale, professional web development.
Key Features of Ext JS
- Comprehensive UI Components: From grids to forms, charts to trees, Ext JS provides a plethora of components that allow developers to create any type of application interface with ease.
- Data Management: Ext JS offers a powerful data model and store system that supports automatic binding to UI components. This allows developers to manage and manipulate large datasets efficiently.
- Cross-Browser Compatibility: One of the strongest features of Ext JS is its ability to render seamlessly across all major browsers, even legacy versions of Internet Explorer.
- MVC & MVVM Architecture: Ext JS uses Model-View-Controller (MVC) and Model-View-ViewModel (MVVM) architectures, ensuring a clear separation of concerns and enhancing maintainability.
- Rich Documentation and Community: Ext JS comes with excellent documentation, guides, and community support, making it easier to learn and implement.
What are the Major Use Cases of Ext JS?
Ext JS is widely adopted in a variety of industries, particularly in business and enterprise environments. Below are some of the most common use cases:
1. Enterprise Applications
Ext JS is ideal for creating enterprise-level applications, such as Customer Relationship Management (CRM) systems, Enterprise Resource Planning (ERP) solutions, and Business Intelligence (BI) applications. These applications often require robust data handling capabilities, which Ext JS provides through its powerful stores, models, and data proxies.
Example: A project management tool where multiple users interact with a large amount of data—Ext JS’s grid and chart components allow users to view real-time project statuses, resource allocations, and timelines efficiently.
2. Data-Intensive Applications
Web applications that require the display, sorting, and filtering of large datasets are a perfect match for Ext JS. Its grid component is particularly well-suited for managing and interacting with large volumes of data.
Example: A real-time stock trading platform where users need to see live price feeds, stock history, and trade statistics on large grids.
3. Single-Page Applications (SPA)
Ext JS supports the development of SPAs, where only a single page is loaded, and subsequent interactions with the application load additional data via AJAX without requiring a page reload. This creates a faster, smoother user experience.
Example: A data analytics dashboard that provides real-time data without refreshing the page, allowing users to interact with different charts and tables seamlessly.
4. Admin Dashboards and Management Systems
Ext JS is often used for creating internal management dashboards, where data from various sources needs to be aggregated and presented in an interactive manner. Its dashboard components—grids, charts, and trees—make it easy to present information in a concise and visually appealing manner.
Example: A human resources management system (HRMS) where administrators can view employee data, generate reports, and manage internal workflows.
5. Mobile Applications
Ext JS can be used to build applications that work well on mobile devices. Sencha Touch, an extension of Ext JS, is used to build touch-based applications, optimizing the UI for mobile devices while leveraging the full power of Ext JS.
Example: A mobile CRM application where field agents can access customer information, update records, and view analytics directly on their smartphones.
How Ext JS Works Along with Architecture
Ext JS follows a Model-View-Controller (MVC) and Model-View-ViewModel (MVVM) architecture, providing a structured approach to building scalable applications. Let’s explore how each of these architectural components work together.
1. Models
A model in Ext JS is a representation of the application’s data. It defines the structure of the data, including field names, data types, validation rules, and associations (such as one-to-many or many-to-many). Models interact with stores to fetch, manipulate, and update data.
Example: In a shopping cart application, the model would define the structure of the product (e.g., name, price, quantity), and each product would be an instance of the model.
2. Views
A view is the user interface component that displays data. It is composed of UI elements like grids, forms, buttons, and charts. Views are typically bound to models, meaning when the model’s data changes, the view automatically updates.
Example: In an inventory management system, a view would represent the grid where users can see a list of all products, filter them, and interact with them.
3. Controllers
Controllers handle the logic and behavior of the application. They manage the application’s flow and interact with both views and models. When an event is triggered by the user (e.g., a button click), the controller determines how the data should be manipulated and what view should be updated.
Example: In a task management app, the controller would handle the logic for adding, editing, or deleting tasks when a user interacts with the UI.
4. Stores
A store is a collection of data that is used by views to render content. It serves as an intermediary between models and views. Stores are responsible for fetching data from a backend server, processing it, and providing it to the views.
Example: In a real-time chat application, a store would manage the collection of messages and update the view as new messages are received.
5. Layouts
Ext JS offers layout managers that determine how components are arranged in the view. Layouts help to create flexible, responsive designs, which can adjust the layout of the UI based on screen size, orientation, or user interaction.
Example: A dashboard layout would allow you to organize widgets or charts in a grid-like format, and this layout can adjust dynamically based on the size of the user’s screen.
Basic Workflow of Ext JS
The typical development workflow when working with Ext JS can be summarized in several clear steps:
- Setup the Project
- Install Sencha Cmd, which helps in scaffolding and building the application. Alternatively, you can start a project manually by including Ext JS libraries and dependencies.
- Initialize the project using a specific command or template.
- Define the Model
- Define a model that describes the structure of the data in your application. Models help to enforce data types, constraints, and validation rules.
- Create the Store
- Create a store that will manage a collection of data, either from a local source or from a remote API. Bind the store to the model for easy data management.
- Design the View
- Design the UI components like grids, forms, or charts using Ext JS components. Bind these views to the data (via models and stores) to dynamically update the interface when the data changes.
- Implement the Controller
- Implement logic in the controller to handle user interactions, update the model, and refresh the view when necessary. Controllers should be used to ensure that the business logic is kept separate from the UI.
- Routing and Navigation
- Use Ext JS routing to handle application states and manage navigation. This allows you to define different states in the application (such as views, components, or sections) that users can navigate between.
- Optimize for Production
- Once the application is complete, use Sencha Cmd to optimize the app for production by minifying and compressing JavaScript files.
Step by Step Getting Started Guide for Ext JS
To get started with Ext JS, follow these detailed steps:
1. Install Ext JS
- Download the latest version of Ext JS from the Sencha website.
- Alternatively, install the Sencha Cmd via npm:
npm install -g @sencha/ext-gen
2. Generate a New Ext JS Project
- Generate a new project using Sencha Cmd:
ext-gen app MyExtApp
3. Configure the Project
- Open the generated project folder and modify the
app.jsonfile to define the required dependencies, resources, and components.
4. Create a Simple Model
- Define a simple model in JavaScript that will represent the data structure.
Ext.define('User', {
extend: 'Ext.data.Model',
fields: ['id', 'name', 'email']
});
5. Create a Store
- Create a store to manage the collection of data.
var store = Ext.create('Ext.data.Store', {
model: 'User',
data: [{id: 1, name: 'John', email: 'john@example.com'}]
});
6. Create a Grid View
- Create a grid to display the data.
Ext.create('Ext.grid.Panel', {
title: 'User Grid',
store: store,
columns: [
{ text: 'ID', dataIndex: 'id' },
{ text: 'Name', dataIndex: 'name' },
{ text: 'Email', dataIndex: 'email' }
],
renderTo: Ext.getBody()
});
7. Run the Application
- Run the application using the local server or Sencha Cmd to see it in action.