service-worker-communications: lazy-loading and promptUser

📚 Docs or angular.io bug report

Description

@Injectable()
export class PromptUpdateService {

  constructor(updates: SwUpdate) {
    updates.available.subscribe(event => {
      if (promptUser(event)) {
        updates.activateUpdate().then(() => document.location.reload());
      }
    });
  }
}

Doing this could break lazy-loading in currently running apps, especially if the lazy-loaded chunks use filenames with hashes, which change every version.

1. The documentation seems incomplete. What should we do if we are using lazy-loading but we want our users to update to the latest version of the app?

2. I think it would be helpful to explain what promptUser is too. If it’s function the developer is expected to write himself–which seems to be the case–then that could be made more clear like this:

@Injectable()
export class PromptUpdateService {

  constructor(updates: SwUpdate) {
    updates.available.subscribe(event => {
      if (this.promptUser(event)) {
        updates.activateUpdate().then(() => document.location.reload());
      }
    });
  }

  private promptUser(event: UpdateAvailableEvent): boolean {
    // prompt the user if now would be a good time to reload the app
  }
}

🔬 Minimal Reproduction

What’s the affected URL?**

https://angular.io/guide/service-worker-communications

[gkalpak]

Thx for the info, @kapunahelewong. This looks like an oversight, so look let’s move forward with #37555.

Interestingly, there was a comment about clarifying that bit in the original PR, but it was apparently never addressed: https://github.com/angular/angular/pull/20021#discussion_r149189505

[bob-watson]

P3 to at least reassess where this is after 2 years of nothing happening with it.