Which @angular/* package(s) are relevant/related to the feature request?

No response

Description

Is this a feature request?

Yes

Description

In SSR Angular applications, a common production issue happens after deploying a new version:

Users who still have a previous version loaded in the browser may encounter a ChunkLoadError when navigating, due to stale HTML referencing outdated hashed bundles.

This typically happens because the server returns HTML that is cached or reused, while the underlying JS chunks have changed.

This is not a bug in Angular itself, but rather a missing default or guidance regarding cache strategy for SSR HTML responses.

Current behavior

• Angular SSR does not define any default cache headers for HTML responses
• Developers must manually configure cache headers
• If misconfigured, this can lead to:
  • ChunkLoadError
  • blank screens
  • broken navigation after deployment

Expected behavior

"Angular SSR could provide a safer default or guidance for HTML caching strategy.

For example:

• Set Cache-Control: no-cache, no-store, must-revalidate by default for SSR HTML responses

OR

• Clearly document recommended cache strategies for SSR applications

Why this matters

• This issue is very common in real-world production environments
• It affects application stability after deployments
• It is difficult to diagnose, especially for less experienced developers
• The fix is simple but not obvious

Additional context

This issue can be reproduced locally without CDN:

1. Run an SSR Angular app
2. Open it in the browser
3. Deploy a new version (new build with different hashes)
4. Navigate to a lazy-loaded route
5. Observe ChunkLoadError

Environment

Angular: 21 (SSR)
Node: any
Browser: any

Proposed solution

Proposed solution

Provide a default cache strategy or guidance for SSR HTML responses.

Option 1 (preferred):

• Angular SSR sets Cache-Control: no-cache, no-store, must-revalidate by default for HTML responses

Option 2:

• Add official documentation recommending cache strategies:
  • HTML (SSR): no-cache
  • Assets (JS/CSS with hashes): long-term cache

Option 3 (optional):

• Expose a built-in hook or configuration option to control cache headers in SSR responses

Alternatives considered

Alternatives considered

• Manually configuring cache headers at the server level (e.g., Express, Nginx)
• Adding a global error handler to reload the app on ChunkLoadError

While these approaches work, they are not obvious and require additional knowledge outside Angular.

Providing guidance or safer defaults in Angular SSR would reduce production issues and improve developer experience.