What are the pros and cons of using Sencha Cmd vs Webpack for code splitting and lazy loading in Ext JS?

1 What is Sencha Cmd?

Sencha Cmd is a command-line tool that provides various features for developing, building, and testing Ext JS applications. It can generate application templates, compile and minify your code, create themes and packages, and more. One of the features that Sencha Cmd offers is code splitting and lazy loading, using the Ext.require() method and the dynamic loader. You can use Sencha Cmd to create build profiles that specify which classes and packages are included in each chunk of code, and how they are loaded at runtime.

2 What is Webpack?

Webpack is a popular module bundler that can process and bundle various types of assets, such as JavaScript, CSS, images, fonts, etc. It can also perform code splitting and lazy loading, using the import() function and the splitChunks plugin. You can use Webpack to configure how your code is split into chunks, how they are named, and how they are loaded on demand. Webpack also supports features like hot module replacement, tree shaking, code minification, and more.

3 How to use Sencha Cmd for code splitting and lazy loading?

To use Sencha Cmd for code splitting and lazy loading, you need to create a sencha.cfg file in your application directory, and define your build profiles in the app.builds section. Each profile can have a name, a list of required classes and packages, and a list of excluded classes and packages. For example, you can create a profile called "main" that includes the core classes and packages of your application, and another profile called "admin" that includes the classes and packages related to the admin functionality. Then, you can use the sencha app build command to generate the code chunks for each profile.

To load the code chunks on demand, you need to use the Ext.require() method in your application code, passing the name of the profile as an argument. For example, you can use Ext.require('admin') to load the admin code chunk when the user navigates to the admin section of your application. The dynamic loader will automatically fetch the required code chunk from the server and execute it.

4 How to use Webpack for code splitting and lazy loading?

To use Webpack for code splitting and lazy loading, you need to create a webpack.config.js file in your project root, and configure the entry points, output, and optimization options. The entry points are the files that define the starting points of your code chunks, and the output is the location and name of the generated code chunks. The optimization option is where you can use the splitChunks plugin to customize how your code is split and grouped into chunks. For example, you can use the cacheGroups option to create chunks based on common dependencies, or the maxSize option to limit the size of each chunk.

To load the code chunks on demand, you need to use the import() function in your application code, passing the name of the entry point as an argument. For example, you can use import('./admin.js') to load the admin code chunk when the user navigates to the admin section of your application. The import() function will return a promise that resolves to the exported module of the code chunk.

5 What are the pros and cons of using Sencha Cmd vs Webpack?

Using Sencha Cmd or Webpack to implement code splitting and lazy loading in your Ext JS applications comes with its own set of pros and cons. Sencha Cmd is integrated with Ext JS and provides many features specifically for Ext JS development, such as generating application templates, themes, packages, and documentation. It can also handle the dependencies and loading of Ext JS automatically. However, it is less flexible and customizable than Webpack, may not support some advanced features or scenarios, and may not work well with other types of assets or modules that are not part of Ext JS. On the other hand, Webpack is more flexible and customizable, can support many advanced features and scenarios, can process and bundle various types of assets or modules that are not part of Ext JS, and can work well with many third-party libraries or plugins. However, it is not integrated with Ext JS, may require more configuration and setup to work with Ext JS projects, may not handle the dependencies and loading of Ext JS classes as smoothly as Sencha Cmd, and may have a steeper learning curve and require more maintenance than Sencha Cmd.