React Hooks Deep Dive: useState, useEffect, and Custom Hooks
Master useState, useEffect, useCallback, useMemo, and custom hooks to write cleaner, reusable React code.
Hooks are the standard way to use state and side effects in function components. Here’s a focused guide to the most important ones.
React hooks and state management
Essential hooks
useState — Holds a value and a setter. Use for local UI state (toggles, form fields). Prefer multiple small states over one big object when it simplifies updates.
useEffect — Runs after render. Use for subscriptions, fetch, or syncing to external systems. Always specify dependencies; use cleanup (return function) when you subscribe or add listeners.
useContext — Read a context value. Use for theme, auth, or app-wide config. Keep contexts narrow to avoid unnecessary re-renders.
useCallback / useMemo — Memoize callbacks and values. Use when passing callbacks to optimized children or when a heavy computation depends on specific props/state.
How often teams use hooks (survey, “primary pattern”):
State logic approach in React apps
Custom hooks
Extract logic into functions that call other hooks. Examples: useFetch, useLocalStorage, useDebounce. They keep components thin and logic testable and reusable.
A concise hooks overview:
Pitfalls to avoid
Don’t call hooks conditionally or in loops. Keep dependency arrays honest so effects don’t run too often or with stale closures. Prefer one clear responsibility per effect.
