How can a growing array used as a cache with no eviction policy become a memory leak?

If you keep pushing entries into a cache array/object without ever removing old ones, it grows unbounded for the lifetime of the app, retaining every cached value forever even if most are never accessed again — effectively a slow, self-inflicted leak.

const cache = [];
function cacheResult(key, value) {
  cache.push({ key, value }); // never removed -> unbounded growth
}