The Rerender Tax of Monolithic Stores

Traditional Redux patterns force components to subscribe to store slices and write memoized selectors to avoid cascade rerenders. When "userProfile" updates, every component reading from that slice recalculates even if it only cares about the username field. This creates selector sprawl where teams maintain parallel memoization logic just to prevent performance degradation. The architectural debt compounds as the store grows, requiring constant vigilance around "useSelector" dependencies and "reselect" chains.

Granular Reactivity Through Atomic Subscriptions

Atomic state libraries flip this model by treating state as a dependency graph of independent atoms rather than a monolithic store.

Comparison: Subscription Models

A component reading "userNameAtom" remains inert when "userAgeAtom" updates. The reactivity is native to the subscription model, not bolted on through performance hacks. This inverts the relationship from "subscribe to container, filter what you need" to "subscribe exactly to what you need."

Derived State as Pure Transformation Layer

A critical mistake when adopting atomic state is conflating derived computation with data fetching. Derived atoms must remain synchronous transformations of existing atoms. A "filteredListAtom" that depends on "listAtom" and "filterAtom" computes its value instantly when dependencies shift. Async operations, like fetching user details, belong in separate atoms with their own loading states. This boundary keeps the dependency graph deterministic. When "filterAtom" changes, "filteredListAtom" recalculates immediately without waiting for network calls or managing intermediate loading states in the derived layer.

Middleware Composition Without Provider Nesting

Zustand demonstrates how state infrastructure can disappear from the component tree entirely. Stores are imported modules, not context providers requiring wrapper components. Middleware like "persist" for localStorage sync, "devtools" for time-travel debugging, and "immer" for immutable updates compose through a functional pipeline. Cross-cutting concerns get applied at store creation without polluting component hierarchies with nested providers. A store enhanced with persistence and debugging tools looks identical to components consuming it, compared to Redux where "Provider", "PersistGate", and "DevTools" wrappers create visible infrastructure noise.