import { createSelector, weakMapMemoize } from 'reselect' import type { RootState } from './cacheSizeProblem' const state: RootState = { items: [ { id: 1, category: 'Electronics', name: 'Wireless Headphones' }, { id: 2, category: 'Books', name: 'The Great Gatsby' }, { id: 3, category: 'Home Appliances', name: 'Blender' }, { id: 4, category: 'Stationery', name: 'Sticky Notes' } ] } const selectItemsByCategory = createSelector( [ (state: RootState) => state.items, (state: RootState, category: string) => category ], (items, category) => items.filter(item => item.category === category), { memoize: weakMapMemoize, argsMemoize: weakMapMemoize } ) selectItemsByCategory(state, 'Electronics') // Selector runs selectItemsByCategory(state, 'Electronics') // Cached selectItemsByCategory(state, 'Stationery') // Selector runs selectItemsByCategory(state, 'Electronics') // Still cached!