Caching
Also called: Cache
Keeping a copy of data somewhere faster, so you don't fetch or compute it again every time.
Definition
A cache stores results close to where they are needed: in memory, on disk, in Redis or on a CDN. It makes reads faster and reduces load on the source, at the cost of data that may be stale. Every cache needs a plan for invalidation (when to throw old data away) and a size limit.
In practice
An image loader keeps recently shown thumbnails in an in-memory LRU cache, so scrolling back up doesn't re-download them.
Learn it in context
Lessons that use this term.