Enable `withIncrementalHydration()` by default in for SSR Angular projects

[npapp-dev002]

Command

new

Description

Currently, Angular SSR applications generated with the Angular CLI (ng new --ssr) do not enable withIncrementalHydration() by default. Developers need to manually update the server configuration to opt in to incremental hydration.

Incremental hydration is now the recommended, modern hydration strategy and provides significant UX and performance benefits compared to the legacy full hydration approach. Because of this, it would be beneficial for developers if new SSR projects used this configuration automatically.

Please enable provideClientHydration(withIncrementalHydration()) in all newly generated Angular SSR applications.

Describe the solution you'd like

Suggested change:

When running:

ng new my-app --ssr

the generated app.config.ts (and/or other relevant project scaffolding) should automatically include:

export const appConfig: ApplicationConfig = {
  providers: [
    provideClientHydration(withIncrementalHydration()),
  ]
};

instead of the current default provideClientHydration().

Describe alternatives you've considered

Developers can manually modify app.config.ts to include withIncrementalHydration(), but:

• It is easy to overlook.
• Tutorials and docs are inconsistent.
• It adds friction to adopting SSR best practices.

[alan-agius4]

//cc @AndrewKushnir & @thePunderWoman

[hybrist]

FWIW, I was also surprised when I tried to follow the docs about @defer with hydrate triggers and it "didn't work" in a new project.

[thePunderWoman]

It's too late for us to do this in v21, but yeah, we should enable it by default.

[alan-agius4]

Following a chat with @thePunderWoman, it was mentioned that before doing this we'd likely want to do some changes to the framework such as enable it by default make it default, not just add it in the schematic.