Angular 4 New Features

• Smaller and Faster - 

                    Angular applications smaller and faster

• View Engine -

                     Reduce the size of the generated code for your components

• Animation Package (Angular Animations) -

                    Configure options and set input variables within animations
                    Define reusable animations using animation()
                    Query for inner elements within animations using query()
                    Stagger multiple elements within an animation using stagger()
                     Enable queried elements to trigger their own animations
                    Orchestrate a full-blown animation when routes change
                    Programmatically build/control an animation using AnimationBuilder

•  Angular Forms -

                   Forms validators for min and max attributes

•  Improved *ngIf and *ngFor

                You can now use an if/else style syntax, and assign local variables such as when unrolling  an observable.
             <div *ngIf="userList | async as users; else loading">
             <user-profile *ngFor="let user of users; count as count; index as i" [user]="user">
              User {{i}} of {{count}}
               </user-profile>
             </div>
             <ng-template #loading>Loading...</ng-template>

• TypeScript compatibility

                  Full support for TypeScript 2.2 and 2.3

• Improvements

                  Datepicker, expansion panel, and accordion components
                   Improved support for @angular/platform-server
                  Configurable scrolling strategies for Overlays
                  Strict-null checks and no-unused-params compliance
                 Typography extension to theming 

• HttpClient

                   Introducing HttpClient, a smaller, easier to use, and more powerful library for making HTTP Requests.

• router life cycle events

                        New router life cycle events for Guards and Resolvers. Four new events: GuardsCheckStart, GuardsCheckEnd, ResolveStart, ResolveEnd join the existing set of life cycle event such as NavigationStart