Reducing the Size of Your React Applications with Tree Shaking and Code Splitting

As React applications grow in size and complexity, it becomes increasingly important to optimise their performance and reduce their footprint. Two powerful techniques for achieving this are tree shaking and code splitting, which can help to eliminate unused code and split large applications into smaller, more manageable chunks.

Tree shaking is a term used to describe the process of removing unused exports from a module. This is typically done during the bundling process, using a tool such as Webpack or Rollup. By removing unused code, the resulting bundle can be significantly smaller and more efficient, improving the performance and loading time of an application.

To enable tree shaking in a React application, developers can use the import and export syntax provided by ECMAScript modules. For example, instead of importing a module using the require function, developers can use the import keyword, along with the specific exports they want to use:

import { MyComponent } from './MyModule';

This syntax allows the bundler to determine which exports are actually used in the application, and to eliminate the unused ones.

Code splitting is another technique for optimising the size and performance of React applications. Instead of bundling all of the application code into a single file, code splitting allows developers to split their applications into multiple chunks, which can be loaded on demand as needed.

For example, instead of importing a large module at the top level of an application, developers can use the dynamic import syntax provided by ECMAScript, which allows the module to be loaded asynchronously:

const MyModule = React.lazy(() => import('./MyModule'));

This syntax allows the module to be loaded only when it is needed, improving the initial loading time of the application and reducing its overall size.

By using tree shaking and code splitting together, developers can create smaller, faster, and more efficient React applications. These techniques can help to eliminate unused code and split large applications into manageable chunks, improving the performance and user experience of an application.