React Hooks Explained (Beginner-Friendly)

First: What is a Hook?

A Hook is just a special function React gives you to “plug into” React features like:

• State
• Lifecycle
• Context
• Performance optimization

Hooks always:

• Start with use
• Are called inside components only
• Follow predictable rules

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The Core Hooks (You should learn these)

These are the hooks you’ll use in almost every React app.

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1️⃣ useState — Store changing data

You already know this one 👍

const [count, setCount] = useState(0);

Use it for:

• Form inputs
• Toggles
• Counters
• Loading states

Mental model:

“Component-level variables that cause re-render when changed.”

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2️⃣ useEffect — Run side effects

Also familiar now.

useEffect(() => {
  fetchData();
}, []);

Use it for:

• API calls
• Subscriptions
• Timers
• Logging

Mental model:

“Run this after rendering or when something changes.”

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3️⃣ useContext — Read global data

Used with React Context.

const user = useContext(UserContext);

Use it for:

• Logged-in user
• Theme
• Language

Mental model:

“Read shared data without passing props.”

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Secondary Hooks (Learn after basics)

These make apps cleaner and faster.

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4️⃣ useRef — Store values without re-rendering

const inputRef = useRef(null);

Use it for:

• Accessing DOM elements
• Storing values that shouldn’t trigger UI updates
• Timers, counters, previous values

Example:

inputRef.current.focus();

Mental model:

“A box that holds data across renders without re-rendering.”

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5️⃣ useReducer — Advanced state logic

Alternative to useState.

const [state, dispatch] = useReducer(reducer, initialState);

Use it when:

• State logic is complex
• Many related state updates exist

Backend analogy:

Reducer = controller logic

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6️⃣ useMemo — Cache expensive calculations

const result = useMemo(() => heavyCalculation(data), [data]);

Use it to:

• Prevent unnecessary recalculations
• Improve performance

Mental model:

“Only recalculate if inputs change.”

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7️⃣ useCallback — Cache functions

const handleClick = useCallback(() => {
  doSomething();
}, []);

Use it when:

• Passing functions to child components
• Preventing unnecessary re-renders

Mental model:

“Same function instance unless dependencies change.”

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Advanced / Rare Hooks (Know they exist)

You don’t need these early on, but it’s good to know them.

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8️⃣ useLayoutEffect

Like useEffect, but runs before browser paint.

Use only when:

• You need to measure layout sizes
• You see flickering UI issues

⚠️ Rarely needed.

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9️⃣ useImperativeHandle

Controls what a parent can access from a child component.

Used with forwardRef.

Advanced use cases only.

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10️⃣ useId

Generates unique IDs.

const id = useId();

Useful for:

• Form inputs
• Accessibility (labels)

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Custom Hooks (VERY IMPORTANT)

You can create your own hooks.

function useGroups() {
  const [groups, setGroups] = useState([]);

  useEffect(() => {
    fetchGroups().then(setGroups);
  }, []);

  return groups;
}

Use them to:

• Reuse logic
• Keep components clean

Mental model:

“Extract reusable logic into a function.”

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Beginner Learning Order (Recommended)

Here’s the safe learning path:

1. useState
2. useEffect
3. useContext
4. useRef
5. useReducer
6. useMemo & useCallback
7. Custom Hooks

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What You Should NOT Do as a Beginner 🚫

• Don’t memorize all hooks
• Don’t use useMemo everywhere
• Don’t optimize too early
• Don’t jump to advanced hooks before basics

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Quick Summary Table

Hook	Purpose	Learn When
useState	Local state	Day 1
useEffect	Side effects	Day 1
useContext	Global state	Early
useRef	DOM & mutable values	Early
useReducer	Complex logic	Intermediate
useMemo	Performance	Later
useCallback	Stable functions	Later

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Final Takeaway

You don’t need all hooks to build real apps.
You need to understand a few deeply.

If you master:

• useState
• useEffect
• useContext

You can build most production apps comfortably.