What is Hydration in angular 16?

Angular Hydration: Enhancing Performance and User Experience.

Angular hydration is a critical process in Angular that plays a significant role in restoring a server-side rendered application on the client. By reusing server-rendered DOM structures, preserving the application state, and transferring pre-retrieved data, Angular hydration improves performance and user experience by avoiding redundant DOM node recreation.

Without hydration, when a user's browser receives the server-rendered HTML, it displays it initially. However, as Angular initializes the client-side application, the browser would have to destroy and re-render the DOM. This process can lead to a visible UI flicker and have a detrimental impact on important performance metrics such as First Input Delay (FID) and Largest Contentful Paint (LCP).

With Hydration:  The concept of Angular hydration involves restoring a server-side rendered application on the client side. This process aims to reuse existing DOM elements, preventing visible UI flickers and enhancing overall performance for the user.

To enable Angular hydration in your Angular application, follow these steps:

1. Set up server-side rendering (SSR) using Angular Universal.
2. Import the provideClientHydration function from @angular/platform-browser in your main app component or module.
3. Add provideClientHydration() to the providers list during application bootstrapping or in the root app module.

Here's an example of enabling Angular hydration in the root app module:

typescript
import { provideClientHydration } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

@NgModule({
  declarations: [RootComponent],
  exports: [RootComponent],
  bootstrap: [RootComponent],
  providers: [provideClientHydration()],
})
export class AppModule {}

It's important to note that Angular hydration imposes certain constraints on your application. The DOM structure on the server and client must be consistent. Direct DOM manipulation should be avoided as it can cause errors during the hydration process. If necessary, you can use the ngSkipHydration attribute to skip hydration for specific components that don't work well with hydration.

By following these steps and utilizing Angular hydration effectively, you can maximize the benefits of server-side rendering and significantly improve the performance and user experience of your Angular application.

Also, Read:

1. Angular 16 & 17 — game changer or loss of identity?

2. Best Front End Programming Languages that You Should Know About

3. What is authentication and authorization in Angular?Example