Refactor init in public/src/admin/appearance/themes.js

[mhk2-cmu]

Refactor init in public/src/admin/appearance/themes.js

Summary

This PR refactors the init function in public/src/admin/appearance/themes.js to address a high complexity code smell detected by Qlty. The original init function contained deeply nested logic for theme selection and multiple inline operations.

The refactor improves readability and maintainability by:

• Adding a guard clause to reduce nesting (if (action !== 'use') return;).
• Extracting a helper function getThemeInfoFrom to encapsulate DOM attribute lookups.
• Extracting applyTheme to handle socket emission and UI updates.
• Simplifying the main init body, which makes the control flow easier to follow.

Evidence of Improvement

Before

Qlty reported:

public/src/admin/appearance/themes.js: Function init has high complexity (count = 13).

After

After the refactor, complexity smell was removed. Qlty now reports:

public/src/admin/appearance/themes.js: Function with many returns (count = 6): init

This remaining warning is due to inline callbacks inside init (returns in nested functions). However, the structure is significantly cleaner and more maintainable.

Manual Validation

• Rebuilt and restarted NodeBB.
• Verified theme selection works as expected.
• Confirmed debug log in browser console:

DEBUG: N624-debu — Themes.init triggered

Issue Link

Resolves CMU-17313Q#46