(fix)O3-4372:Feature flags that no longer exist should be removed from local storage

[Bharath-K-Shetty]

Requirements

• This PR has a title that briefly describes the work done including the ticket number. Ensure your PR title includes a conventional commit label (such as feat, fix, or chore, among others). See existing PR titles for inspiration.

For changes to apps

• My work conforms to the O3 Styleguide and design documentation.

If applicable

• My work includes tests or is validated by existing tests.
• I have updated the esm-framework mock to reflect any API changes I have made.

Summary

This pull request addresses the issue of removing feature flags that no longer exist from local storage. The following changes have been made:

1. Added cleanupObsoleteFeatureFlags function: This function removes feature flags from local storage that no longer exist in the current state.

2. Called cleanupObsoleteFeatureFlags within featureFlagsStore.subscribe: Ensures that obsolete feature flags are cleaned up whenever the state is updated.

3. Called cleanupObsoleteFeatureFlags within registerFeatureFlag: Ensures that obsolete feature flags are cleaned up whenever a new feature flag is registered.

Testing
To verify the functionality, the following steps were performed:

1. Registered a new feature flag:

registerFeatureFlag('testFlag', 'Test Flag', 'This is a test flag');

2. Checked local storage:

• Opened the browser's developer tools.

• Navigated to the "Application" tab

• Verified that the key openmrs:feature-flag:testFlag was present in local storage.

3. Removed the feature flag from the application's state:

window.featureFlagsStore.setState((state) => {
  const { testFlag, ...remainingFlags } = state.flags;
  return { flags: remainingFlags };
});

4. Checked local storage again:

• Verified that the key openmrs:feature-flag:testFlag was removed from local storage.

Screenshots

Screen.Recording.2025-01-23.165035.mp4

Related Issue

https://openmrs.atlassian.net/browse/O3-4372

Other

[Bharath-K-Shetty]

@ibacher review required..!Thanks

[ibacher]

Thanks @Bharath-K-Shetty! So, the deletion code looks correct, but I don't think calling it at the two points that this PR does will delete them at the right point. This is because registerFeatureFlag() is called as each feature flag is registered, which means, on each run, this would—presumably—delete all existing flags from local storage, which is not what we want.

We need to find a point in the app start-up cycle when the feature flags will all be registered to call this, so likely at some point in the app shell itself.

[Bharath-K-Shetty]

@ibacher, as you suggested, I moved the cleanupObsoleteFeatureFlags function to core-config.ts so that it runs at app startup. However, I’ve encountered a challenge: the cleanup function in core-config.ts gets called before all the feature flags are registered. This causes the cleanup logic to fail, as it requires all flags to be registered beforehand.

Would using promises be a viable solution to ensure that the cleanup logic runs only after all the flags are registered?

Additionally, while logging, I noticed that the billing module is not registering its feature flags. Could you provide guidance on what steps I should take to address both these issues?