HOW TO
Cache Intermediate Data
Goal
Cache expensive or reused intermediate data in a workbook workflow.
Prerequisites
- A repeated or expensive intermediate array worth keeping in add-in memory.
- A cache key naming convention, unless the cache will be read once inside a nested formula.
Steps
1. Choose a cache key that is unique to the workbook workflow.
2. Cache the expensive source range under that key.
3. Pass the cache key to downstream U functions, or retrieve its content for native Excel formulas.
4. Set an expiry only after reviewing the staleness risk for the workflow.
Result
Downstream U functions reuse the cached data by key without redisplaying or recomputing the full source range.
Common Variations
- Omit the key for a read-once cache consumed by the next nested U function.
- Filter pages while caching a multi-page report.
- Set an expiry for data that must age out automatically.
Troubleshooting
- Native Excel functions cannot read a cache key directly; retrieve the data with
U.GETfirst. - A named cache persists until overwritten, removed, expired, or the Excel instance closes.
- If freshness is unclear, display the cache result and its update trigger separately.