WELCOME TO ANGULAR 19

First of all, I would like to thank the whole Angular team for providing such great features in Angular 19.It comes up with a lot of new features such as Hot module replacement,Incremental hydration, linked signals, standalone defaults, Timepicker component, Resource APIs.

Top new features of Angular 19:

• Hot Module Replacement
• Incremental Hydration
• Linked Signals
• Standalone defaults
• TimePicker component
• Resource APIs

1.Hot Module replacement :-

Angular 19 have focused on Hot module replacement.This feature will speed up the time on page load.Previously any change in style or templates will rebuild the whole application, but now it just applies the patch and does not refresh the whole application and browser refresh.The HMR efficiently compiles the modified style or templates alone.This definitely helps in faster development of web applications. For example, you have filled the whole page with some data,but atlast you observe that one button is having red color, instead of blue.In this case if you change the style of the button, entire application will gets refreshed prior to Angular19.But after introducing HMR in angular19, it just patches that style alone and not the whole page, so that the data on that component or page is preserved.you can see the HMR changes in your browser console. In this console, you can see which css has changed and which component has been changed with some random number.

2.Incremental Hydration :-

An incremental hydration will hydrate specific parts of the application on demand.This is performed by @defer syntax, tells angular to lazy load and hydrate on calling specific triggers.I know you will be thinking, where to write this incremental hydration in the code.This is how your app.config looks like:

 import { provideClientHydration, withIncrementalHydration } from '@angular/platform-browser';
bootstrapApplication(AppComponent, {
  providers: [
    provideClientHydration(withIncrementalHydration())
  ]
});

3.Linked Signals:-

Angular 19 introduces a new feature called linked signals.It helps to manage state with other signals.The following are the characteristics of linked signals.

• Writable signals:Here we can update value of signal manually like other signals.
• Reuse computed signals: we can reuse computed signals in other form using linked signals.

                        a=signal(10);
                         b=linkedsignal(()=>2*a());
                        c=computedsignal(()=>2*a());
                       
                        a.set(20);
                        b.set(30); //Correct - not able to set computed signal
                        c.set(40); // Wrong

4.Standalone defaults:-

Standalone components makes developers life easy, no need to declare or add dependency components,services in seperate module. Instead just make standalone as true in component itself. In Angular 19, components,directives and pipes are marked as standalone. The classes which are marked as standalone do not need to be declared in Ngmodule.

                        @component ({
                            selector:'Acomponent',
                            standalone:true,
                            imports:[] //add dependency components

                        })
                        export class Acomponent{}

5.TimePicker component:-

Angular 19 provides a built in Timepicker component that allows users to select a specific time.Angular material provides new user friendly Timepicker component which allows user to easily choose time with more predefined options such as by using interval options,predefined options etc.

                      <mat-form-field>
                                             <mat-label>Pick a time<mat-label>
                                             <input matInput [matTimepicker]="picker">
                                             <mat-timepicker-toggle matIconSuffix [for]="picker" >
                                             <mat-timepicker #picker >
                       <mat-form-field>

6.Resource APIs :-

Angular 19 introduces new brand import called Resource from angular core package.This resource api is extremely useful in asynchronous calls. Normally during data fetch we will use following operations like fetch data, reload data and clear data.Previously we will be writing seperate functions to fetch data,reload data and clear data.But now in our new Resource class in angular 19 has made everything simple by introducing inbuilt methods inside this resource class for accessing fetch ,reload and clear data. The following are the functions used inside this resource API,

• loader
• request

products=resource({
                            loader:async()={
                        const products=await fetch(`${API_URL}`);
                        return await products.json();
                        }

});
                
                    

• value
• reLoad
• set
• error
• isLoading
• status