React hook setiap pembangun JavaScript mesti menanda halaman

React ialah perpustakaan JavaScript sumber terbuka untuk membina antara muka pengguna yang hebat dan kompleks dan merupakan salah satu yang paling popular dalam ekosistem JavaScript.

TLDR ?

Cakuk React ialah fungsi yang membolehkan anda menggunakan keadaan React dan ciri lain dalam komponen berfungsi, membolehkan tugas seperti mengendalikan kesan sampingan dan mengakses konteks tanpa menulis kelas React yang kompleks. Menggunakan cangkuk React juga meningkatkan kebolehbacaan dan kebolehselenggaraan kod untuk pembangun.

Dalam artikel ini, saya akan berkongsi senarai 38 cangkuk React.js dan kes penggunaannya, yang boleh dianggap sebagai salah satu sumber terbaik untuk pembangun React dan JavaScript.

1. useState

Mengurus keadaan komponen setempat.

import { useState } from 'react';
function Counter() {
  const [count, setCount] = useState(0);
  return (
    <div>
      <button onClick={() => setCount(count + 1)}>Increment</button>
      <p>Count: {count}</p>
    </div>
  );
}

2. kegunaanKesan

Melakukan kesan sampingan dalam komponen fungsi.

import { useEffect, useState } from 'react';

function DataFetcher() {
  const [data, setData] = useState(null);

  useEffect(() => {
    fetch('https://api.example.com/data')
      .then(response => response.json())
      .then(data => setData(data));
  }, []);

  return <div>Data: {data ? JSON.stringify(data) : 'Loading...'}</div>;
}

3. gunakanKonteks

Menggunakan konteks dalam komponen.

import { useContext } from 'react';
import { ThemeContext } from './ThemeContext';

function ThemedButton() {
  const theme = useContext(ThemeContext);
  return <button style={{ background: theme.background }}>Click me</button>;
}

4.useReducer

Mengurus logik keadaan kompleks

import { useReducer } from 'react';

const initialState = { count: 0 };

function reducer(state, action) {
  switch (action.type) {
    case 'increment':
      return { count: state.count + 1 };
    case 'decrement':
      return { count: state.count - 1 };
    default:
      throw new Error();
  }
}

function Counter() {
  const [state, dispatch] = useReducer(reducer, initialState);
  return (
    <div>
      <button onClick={() => dispatch({ type: 'decrement' })}>-</button>
      <span>{state.count}</span>
      <button onClick={() => dispatch({ type: 'increment' })}>+</button>
    </div>
  );
}

5. gunakanPanggil balik

Mengembalikan fungsi panggil balik yang diingati.

import { useCallback, useState } from 'react';

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

  const increment = useCallback(() => {
    setCount(count + 1);
  }, [count]);

  return <button onClick={increment}>Count: {count}</button>;
}

6. gunakanMemo

Menghafal pengiraan mahal iaitu menyimpan hasil pengiraan intensif sumber untuk kegunaan masa hadapan.

import { useMemo, useState } from 'react';

function Fibonacci() {
  const [num, setNum] = useState(1);

  const fib = useMemo(() => {
    const computeFib = (n) => (n <= 1 ? n : computeFib(n - 1) + computeFib(n - 2));
    return computeFib(num);
  }, [num]);

  return (
    <div>
      <button onClick={() => setNum(num + 1)}>Next Fibonacci</button>
      <p>Fibonacci of {num} is {fib}</p>
    </div>
  );
}

7.gunaRujuk

Mengakses elemen DOM atau menyimpan nilai boleh ubah.

import { useRef } from 'react';

function TextInputWithFocusButton() {
  const inputEl = useRef(null);
  const onButtonClick = () => {
    inputEl.current.focus();
  };

  return (
    <div>
      <input ref={inputEl} type="text" />
      <button onClick={onButtonClick}>Focus the input</button>
    </div>
  );
}

8.gunakanImperativeHandle

Menyesuaikan nilai tika yang didedahkan oleh rujukan.

import { forwardRef, useImperativeHandle, useRef } from 'react';

const FancyInput = forwardRef((props, ref) => {
  const inputRef = useRef();
  useImperativeHandle(ref, () => ({
    focus: () => {
      inputRef.current.focus();
    },
  }));
  return <input ref={inputRef} />;
});

function App() {
  const fancyInputRef = useRef();
  return (
    <div>
      <FancyInput ref={fancyInputRef} />
      <button onClick={() => fancyInputRef.current.focus()}>Focus input</button>
    </div>
  );
}

9. useLayoutEffect

Menyegerakkan dengan reka letak DOM.

import { useEffect, useLayoutEffect, useRef, useState } from 'react';

function MeasureWidth() {
  const ref = useRef();
  const [width, setWidth] = useState(0);

  useLayoutEffect(() => {
    setWidth(ref.current.offsetWidth);
  }, []);

  return (
    <div>
      <div ref={ref} style={{ width: '50%' }}>
        Resize the window to see the effect.
      </div>
      <p>Width: {width}px</p>
    </div>
  );
}

10.useDebugValue

Memaparkan label tersuai dalam React DevTools.

import { useDebugValue, useState } from 'react';

function useFriendStatus(friendID) {
  const [isOnline, setIsOnline] = useState(null);

  useDebugValue(isOnline ? 'Online' : 'Offline');

  // Simulate an asynchronous operation
  setTimeout(() => setIsOnline(Math.random() > 0.5), 1000);

  return isOnline;
}

function FriendStatus({ friendID }) {
  const isOnline = useFriendStatus(friendID);

  if (isOnline === null) {
    return 'Loading...';
  }
  return isOnline ? 'Online' : 'Offline';
}

11.useFetch

Mengambil data daripada API.

import { useEffect, useState } from 'react';

function useFetch(url) {
  const [data, setData] = useState(null);
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    fetch(url)
      .then(response => response.json())
      .then(data => {
        setData(data);
        setLoading(false);
      });
  }, [url]);

  return { data, loading };
}

function App() {
  const { data, loading } = useFetch('https://jsonplaceholder.typicode.com/posts');

  if (loading) {
    return <p>Loading...</p>;
  }

  return (
    <ul>
      {data.map(post => (
        <li key={post.id}>{post.title}</li>
      ))}
    </ul>
  );
}

12.useLocalStorage

Mengurus negeri dengan storan setempat.

import { useState } from 'react';

function useLocalStorage(key, initialValue) {
  const [storedValue, setStoredValue] = useState(() => {
    try {
      const item = window.localStorage.getItem(key);
      return item ? JSON.parse(item) : initialValue;
    } catch (error) {
      console.error(error);
      return initialValue;
    }
  });

  const setValue = (value) => {
    try {
      const valueToStore = value instanceof Function ? value(storedValue) : value;
      setStoredValue(valueToStore);
      window.localStorage.setItem(key, JSON.stringify(valueToStore));
    } catch (error) {
      console.error(error);
    }
  };

  return [storedValue, setValue];
}

function App() {
  const [name, setName] = useLocalStorage('name', 'Bob');

  return (
    <div>
      <input value={name} onChange={(e) => setName(e.target.value)} />
      <p>Hello, {name}!</p>
    </div>
  );
}

13. gunakanDebounce

Menyahlantunkan nilai dari semasa ke semasa.

import { useEffect, useState } from 'react';

function useDebounce(value, delay) {
  const [debouncedValue, setDebouncedValue] = useState(value);

  useEffect(() => {
    const handler = setTimeout(() => {
      setDebouncedValue(value);
    }, delay);

    return () => {
      clearTimeout(handler);
    };
  }, [value, delay]);

  return debouncedValue;
}

function App() {
  const [text, setText] = useState('');
  const debouncedText = useDebounce(text, 500);

  return (
    <div>
      <input value={text} onChange={(e) => setText(e.target.value)} />
      <p>Debounced Value: {debouncedText}</p>
    </div>
  );
}

14.penggunaanSebelumnya

Menyimpan nilai sebelumnya pembolehubah.

import { useEffect, useRef } from 'react';

function usePrevious(value) {
  const ref = useRef();

  useEffect(() => {
    ref.current = value;
  }, [value]);

  return ref.current;
}

function App() {
  const [count, setCount] = useState(0);
  const previousCount = usePrevious(count);

  return (
    <div>
      <button onClick={() => setCount(count + 1)}>Count: {count}</button>
      <p>Previous Count: {previousCount}</p>
    </div>
  );
}

15. gunakanWindowSize

Menjejaki saiz tetingkap.

import { useEffect, useState } from 'react';

function useWindowSize() {
  const [size, setSize] = useState({ width: window.innerWidth, height: window.innerHeight });

  useEffect(() => {
    const handleResize = () => {
      setSize({ width: window.innerWidth, height: window.innerHeight });
    };

    window.addEventListener('resize', handleResize);
    return () => window.removeEventListener('resize', handleResize);
  }, []);

  return size;
}

function App() {
  const { width, height } = useWindowSize();

  return (
    <div>
      <p>Width: {width}px</p>
      <p>Height: {height}px</p>
    </div>
  );
}

16.useHover

Mengesan jika elemen dilegar.

import { useCallback, useState } from 'react';

function useHover() {
  const [hovered, setHovered] = useState(false);

  const onMouseOver = useCallback(() => setHovered(true), []);
  const onMouseOut = useCallback(() => setHovered(false), []);

  return { hovered, onMouseOver, onMouseOut };
}

function HoverComponent() {
  const { hovered, onMouseOver, onMouseOut } = useHover();

  return (
    <div onMouseOver={onMouseOver} onMouseOut={onMouseOut}>
      {hovered ? 'Hovering' : 'Not Hovering'}
    </div>
  );
}

17. gunakanOnlineStatus

Menjejaki status dalam talian.

import { useEffect, useState } from 'react';

function useOnlineStatus() {
  const [isOnline, setIsOnline] = useState(navigator.onLine);

  useEffect(() => {
    const handleOnline = () => setIsOnline(true);
    const handleOffline = () => setIsOnline(false);

    window.addEventListener('online', handleOnline);
    window.addEventListener('offline', handleOffline);

    return () => {
      window.removeEventListener('online', handleOnline);
      window.removeEventListener('offline', handleOffline);
    };
  }, []);

  return isOnline;
}

function App() {
  const isOnline = useOnlineStatus();

  return <div>{isOnline ? 'Online' : 'Offline'}</div>;
}

18. gunakanEventListener

Melampirkan pendengar acara.

import { useEffect, useRef } from 'react';

function useEventListener(eventName, handler, element = window) {
  const savedHandler = useRef();

  useEffect(() => {
    savedHandler.current = handler;
  }, [handler]);

  useEffect(() => {
    const eventListener = (event) => savedHandler.current(event);
    element.addEventListener(eventName, eventListener);

    return () => {
      element.removeEventListener(eventName, eventListener);
    };
  }, [eventName, element]);
}

function App() {
  useEventListener('click', () => alert('Window clicked!'));

  return <div>Click anywhere!</div>;
}

19.useInterval

Sediakan selang waktu dengan kelewatan dinamik.

import { useEffect, useRef } from 'react';

function useInterval(callback, delay) {
  const savedCallback = useRef();

  useEffect(() => {
    savedCallback.current = callback;
  }, [callback]);

  useEffect(() => {
    function tick() {
      savedCallback.current();
    }
    if (delay !== null) {
      const id = setInterval(tick, delay);
      return () => clearInterval(id);
    }
  }, [delay]);
}

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

  useInterval(() => setCount(count + 1), 1000);

  return <div>Count: {count}</div>;
}

20. useTimeout

Sediakan tamat masa.

import { useState } from 'react';
function Counter() {
  const [count, setCount] = useState(0);
  return (
    <div>
      <button onClick={() => setCount(count + 1)}>Increment</button>
      <p>Count: {count}</p>
    </div>
  );
}

21. gunakanOnClickOutside

Mengesan klik di luar komponen.

import { useEffect, useState } from 'react';

function DataFetcher() {
  const [data, setData] = useState(null);

  useEffect(() => {
    fetch('https://api.example.com/data')
      .then(response => response.json())
      .then(data => setData(data));
  }, []);

  return <div>Data: {data ? JSON.stringify(data) : 'Loading...'}</div>;
}

22. gunakanPapan Klip

Mengendalikan operasi papan keratan.

import { useContext } from 'react';
import { ThemeContext } from './ThemeContext';

function ThemedButton() {
  const theme = useContext(ThemeContext);
  return <button style={{ background: theme.background }}>Click me</button>;
}

23. gunakanDarkMode

Mengurus pilihan mod gelap.

import { useReducer } from 'react';

const initialState = { count: 0 };

function reducer(state, action) {
  switch (action.type) {
    case 'increment':
      return { count: state.count + 1 };
    case 'decrement':
      return { count: state.count - 1 };
    default:
      throw new Error();
  }
}

function Counter() {
  const [state, dispatch] = useReducer(reducer, initialState);
  return (
    <div>
      <button onClick={() => dispatch({ type: 'decrement' })}>-</button>
      <span>{state.count}</span>
      <button onClick={() => dispatch({ type: 'increment' })}>+</button>
    </div>
  );
}

24.useTogol

Menukar antara nilai boolean.

import { useCallback, useState } from 'react';

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

  const increment = useCallback(() => {
    setCount(count + 1);
  }, [count]);

  return <button onClick={increment}>Count: {count}</button>;
}

25. gunakanTema

Bertukar antara tema terang dan gelap.

import { useMemo, useState } from 'react';

function Fibonacci() {
  const [num, setNum] = useState(1);

  const fib = useMemo(() => {
    const computeFib = (n) => (n <= 1 ? n : computeFib(n - 1) + computeFib(n - 2));
    return computeFib(num);
  }, [num]);

  return (
    <div>
      <button onClick={() => setNum(num + 1)}>Next Fibonacci</button>
      <p>Fibonacci of {num} is {fib}</p>
    </div>
  );
}

26. gunakanMedia

Mempertanyakan sifat media.

import { useRef } from 'react';

function TextInputWithFocusButton() {
  const inputEl = useRef(null);
  const onButtonClick = () => {
    inputEl.current.focus();
  };

  return (
    <div>
      <input ref={inputEl} type="text" />
      <button onClick={onButtonClick}>Focus the input</button>
    </div>
  );
}

27. gunakanLockBodyScroll

Mengunci skrol badan.

import { forwardRef, useImperativeHandle, useRef } from 'react';

const FancyInput = forwardRef((props, ref) => {
  const inputRef = useRef();
  useImperativeHandle(ref, () => ({
    focus: () => {
      inputRef.current.focus();
    },
  }));
  return <input ref={inputRef} />;
});

function App() {
  const fancyInputRef = useRef();
  return (
    <div>
      <FancyInput ref={fancyInputRef} />
      <button onClick={() => fancyInputRef.current.focus()}>Focus input</button>
    </div>
  );
}

28.useKeyPress

Mengesan penekanan kekunci.

import { useEffect, useLayoutEffect, useRef, useState } from 'react';

function MeasureWidth() {
  const ref = useRef();
  const [width, setWidth] = useState(0);

  useLayoutEffect(() => {
    setWidth(ref.current.offsetWidth);
  }, []);

  return (
    <div>
      <div ref={ref} style={{ width: '50%' }}>
        Resize the window to see the effect.
      </div>
      <p>Width: {width}px</p>
    </div>
  );
}

29. gunakanDocumentTitle

Mengemas kini tajuk dokumen.

import { useDebugValue, useState } from 'react';

function useFriendStatus(friendID) {
  const [isOnline, setIsOnline] = useState(null);

  useDebugValue(isOnline ? 'Online' : 'Offline');

  // Simulate an asynchronous operation
  setTimeout(() => setIsOnline(Math.random() > 0.5), 1000);

  return isOnline;
}

function FriendStatus({ friendID }) {
  const isOnline = useFriendStatus(friendID);

  if (isOnline === null) {
    return 'Loading...';
  }
  return isOnline ? 'Online' : 'Offline';
}

30. useHover

Mengendalikan keadaan tuding.

import { useEffect, useState } from 'react';

function useFetch(url) {
  const [data, setData] = useState(null);
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    fetch(url)
      .then(response => response.json())
      .then(data => {
        setData(data);
        setLoading(false);
      });
  }, [url]);

  return { data, loading };
}

function App() {
  const { data, loading } = useFetch('https://jsonplaceholder.typicode.com/posts');

  if (loading) {
    return <p>Loading...</p>;
  }

  return (
    <ul>
      {data.map(post => (
        <li key={post.id}>{post.title}</li>
      ))}
    </ul>
  );
}

31.gunakanGeolokasi

Mengambil geolokasi.

import { useState } from 'react';

function useLocalStorage(key, initialValue) {
  const [storedValue, setStoredValue] = useState(() => {
    try {
      const item = window.localStorage.getItem(key);
      return item ? JSON.parse(item) : initialValue;
    } catch (error) {
      console.error(error);
      return initialValue;
    }
  });

  const setValue = (value) => {
    try {
      const valueToStore = value instanceof Function ? value(storedValue) : value;
      setStoredValue(valueToStore);
      window.localStorage.setItem(key, JSON.stringify(valueToStore));
    } catch (error) {
      console.error(error);
    }
  };

  return [storedValue, setValue];
}

function App() {
  const [name, setName] = useLocalStorage('name', 'Bob');

  return (
    <div>
      <input value={name} onChange={(e) => setName(e.target.value)} />
      <p>Hello, {name}!</p>
    </div>
  );
}

32. gunakanScrollPosition

Menjejaki kedudukan tatal.

import { useEffect, useState } from 'react';

function useDebounce(value, delay) {
  const [debouncedValue, setDebouncedValue] = useState(value);

  useEffect(() => {
    const handler = setTimeout(() => {
      setDebouncedValue(value);
    }, delay);

    return () => {
      clearTimeout(handler);
    };
  }, [value, delay]);

  return debouncedValue;
}

function App() {
  const [text, setText] = useState('');
  const debouncedText = useDebounce(text, 500);

  return (
    <div>
      <input value={text} onChange={(e) => setText(e.target.value)} />
      <p>Debounced Value: {debouncedText}</p>
    </div>
  );
}

33. gunakanNyahlekap

Menjalankan fungsi apabila komponen dinyahlekap.

import { useEffect, useRef } from 'react';

function usePrevious(value) {
  const ref = useRef();

  useEffect(() => {
    ref.current = value;
  }, [value]);

  return ref.current;
}

function App() {
  const [count, setCount] = useState(0);
  const previousCount = usePrevious(count);

  return (
    <div>
      <button onClick={() => setCount(count + 1)}>Count: {count}</button>
      <p>Previous Count: {previousCount}</p>
    </div>
  );
}

34. gunakanClickOutside

Mengesan klik di luar elemen.

import { useEffect, useState } from 'react';

function useWindowSize() {
  const [size, setSize] = useState({ width: window.innerWidth, height: window.innerHeight });

  useEffect(() => {
    const handleResize = () => {
      setSize({ width: window.innerWidth, height: window.innerHeight });
    };

    window.addEventListener('resize', handleResize);
    return () => window.removeEventListener('resize', handleResize);
  }, []);

  return size;
}

function App() {
  const { width, height } = useWindowSize();

  return (
    <div>
      <p>Width: {width}px</p>
      <p>Height: {height}px</p>
    </div>
  );
}

35. gunakanDebouncedCallback

Menyahlantunkan fungsi panggil balik.

import { useCallback, useState } from 'react';

function useHover() {
  const [hovered, setHovered] = useState(false);

  const onMouseOver = useCallback(() => setHovered(true), []);
  const onMouseOut = useCallback(() => setHovered(false), []);

  return { hovered, onMouseOver, onMouseOut };
}

function HoverComponent() {
  const { hovered, onMouseOver, onMouseOut } = useHover();

  return (
    <div onMouseOver={onMouseOver} onMouseOut={onMouseOut}>
      {hovered ? 'Hovering' : 'Not Hovering'}
    </div>
  );
}

36. useThrottle

Mendikit nilai dari semasa ke semasa.

import { useEffect, useState } from 'react';

function useOnlineStatus() {
  const [isOnline, setIsOnline] = useState(navigator.onLine);

  useEffect(() => {
    const handleOnline = () => setIsOnline(true);
    const handleOffline = () => setIsOnline(false);

    window.addEventListener('online', handleOnline);
    window.addEventListener('offline', handleOffline);

    return () => {
      window.removeEventListener('online', handleOnline);
      window.removeEventListener('offline', handleOffline);
    };
  }, []);

  return isOnline;
}

function App() {
  const isOnline = useOnlineStatus();

  return <div>{isOnline ? 'Online' : 'Offline'}</div>;
}

37. useUpdateEffect

Menjalankan kesan hanya pada kemas kini, bukan pada pelekap.

import { useEffect, useRef } from 'react';

function useEventListener(eventName, handler, element = window) {
  const savedHandler = useRef();

  useEffect(() => {
    savedHandler.current = handler;
  }, [handler]);

  useEffect(() => {
    const eventListener = (event) => savedHandler.current(event);
    element.addEventListener(eventName, eventListener);

    return () => {
      element.removeEventListener(eventName, eventListener);
    };
  }, [eventName, element]);
}

function App() {
  useEventListener('click', () => alert('Window clicked!'));

  return <div>Click anywhere!</div>;
}

38.useLocalStorage

Mengurus keadaan dalam storan setempat

import { useEffect, useRef } from 'react';

function useInterval(callback, delay) {
  const savedCallback = useRef();

  useEffect(() => {
    savedCallback.current = callback;
  }, [callback]);

  useEffect(() => {
    function tick() {
      savedCallback.current();
    }
    if (delay !== null) {
      const id = setInterval(tick, delay);
      return () => clearInterval(id);
    }
  }, [delay]);
}

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

  useInterval(() => setCount(count + 1), 1000);

  return <div>Count: {count}</div>;
}

React.js mudah dipelajari dan dikuasai, dengan banyak kursus dan sumber percuma, serta komuniti pembangun yang besar dan aktif
Pastikan anda menggunakan cangkuk React ini dalam projek anda yang seterusnya dan ikuti saya untuk lebih banyak kandungan seperti ini

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Editor Kandungan Teknikal & Penulis

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