- Moved heavy tag counting and IDF calculation to `js/workers/exploreData.worker.js`.
- Extracted `collectVideoTags` to `js/utils/videoTags.js` (preserved original behavior).
- Extracted pointer normalization logic to `js/utils/pointerNormalization.js`.
- Refactored `js/services/exploreDataService.js` to use the worker.
- Added benchmark test `tests/benchmark-explore-data.spec.mjs`.
Measured Improvement:
- `buildTagIdf` execution time on main thread reduced from ~130ms blocking to ~0ms blocking (141ms total async time).
- Unblocks UI during periodic data refreshes.
Co-authored-by: PR0M3TH3AN <[email protected]>
