بروزرسانی آرایه وضعیت در React

      import { useState } from 'react';

let nextId = 0;

export default function List() {
  const [name, setName] = useState('');
  const [artists, setArtists] = useState([]);

  return (
    <>
      <h1>Inspiring sculptors:</h1>
      <input
        value={name}
        onChange={e => setName(e.target.value)}
      />
      <button onClick={() => {
        artists.push({
          id: nextId++,
          name: name,
        });
      }}>Add</button>
      <ul>
        {artists.map(artist => (
          <li key={artist.id}>{artist.name}</li>
        ))}
      </ul>
    </>
  );
}
    

      setArtists( // وضعیت را بروز کن
  [ // با آرایه ای جدید
    ...artists, // که شامل تمامی آیتم های قدیم است
    { id: nextId++, name: name } // و یک آیتم جدید در انتها به آن اضافه شده
  ]
);
    

      import { useState } from 'react';

let nextId = 0;

export default function List() {
  const [name, setName] = useState('');
  const [artists, setArtists] = useState([]);

  return (
    <>
      <h1>Inspiring sculptors:</h1>
      <input
        value={name}
        onChange={e => setName(e.target.value)}
      />
      <button onClick={() => {
        setArtists([
          ...artists,
          { id: nextId++, name: name }
        ]);
      }}>Add</button>
      <ul>
        {artists.map(artist => (
          <li key={artist.id}>{artist.name}</li>
        ))}
      </ul>
    </>
  );
}
    

      setArtists([
  { id: nextId++, name: name },
  ...artists // Put old items at the end
]);
    

      import { useState } from 'react';

let initialArtists = [
  { id: 0, name: 'Marta Colvin Andrade' },
  { id: 1, name: 'Lamidi Olonade Fakeye'},
  { id: 2, name: 'Louise Nevelson'},
];

export default function List() {
  const [artists, setArtists] = useState(
    initialArtists
  );

  return (
    <>
      <h1>Inspiring sculptors:</h1>
      <ul>
        {artists.map(artist => (
          <li key={artist.id}>
            {artist.name}{' '}
            <button onClick={() => {
              setArtists(
                artists.filter(a =>
                  a.id !== artist.id
                )
              );
            }}>
              Delete
            </button>
          </li>
        ))}
      </ul>
    </>
  );
}
    

      setArtists(
  artists.filter(a => a.id !== artist.id)
);
    

      import { useState } from 'react';

let initialShapes = [
  { id: 0, type: 'circle', x: 50, y: 100 },
  { id: 1, type: 'square', x: 150, y: 100 },
  { id: 2, type: 'circle', x: 250, y: 100 },
];

export default function ShapeEditor() {
  const [shapes, setShapes] = useState(
    initialShapes
  );

  function handleClick() {
    const nextShapes = shapes.map(shape => {
      if (shape.type === 'square') {
        // No change
        return shape;
      } else {
        // Return a new circle 50px below
        return {
          ...shape,
          y: shape.y + 50,
        };
      }
    });
    // Re-render with the new array
    setShapes(nextShapes);
  }

  return (
    <>
      <button onClick={handleClick}>
        Move circles down!
      </button>
      {shapes.map(shape => (
        <div
          key={shape.id}
          style={{
          background: 'purple',
          position: 'absolute',
          left: shape.x,
          top: shape.y,
          borderRadius:
            shape.type === 'circle'
              ? '50%' : '',
          width: 20,
          height: 20,
        }} />
      ))}
    </>
  );
}
    

      import { useState } from 'react';

let initialCounters = [
  0, 0, 0
];

export default function CounterList() {
  const [counters, setCounters] = useState(
    initialCounters
  );

  function handleIncrementClick(index) {
    const nextCounters = counters.map((c, i) => {
      if (i === index) {
        // Increment the clicked counter
        return c + 1;
      } else {
        // The rest haven't changed
        return c;
      }
    });
    setCounters(nextCounters);
  }

  return (
    <ul>
      {counters.map((counter, i) => (
        <li key={i}>
          {counter}
          <button onClick={() => {
            handleIncrementClick(i);
          }}>+1</button>
        </li>
      ))}
    </ul>
  );
}
    

      import { useState } from 'react';

let nextId = 3;
const initialArtists = [
  { id: 0, name: 'Marta Colvin Andrade' },
  { id: 1, name: 'Lamidi Olonade Fakeye'},
  { id: 2, name: 'Louise Nevelson'},
];

export default function List() {
  const [name, setName] = useState('');
  const [artists, setArtists] = useState(
    initialArtists
  );

  function handleClick() {
    const insertAt = 1; // Could be any index
    const nextArtists = [
      // Items before the insertion point:
      ...artists.slice(0, insertAt),
      // New item:
      { id: nextId++, name: name },
      // Items after the insertion point:
      ...artists.slice(insertAt)
    ];
    setArtists(nextArtists);
    setName('');
  }

  return (
    <>
      <h1>Inspiring sculptors:</h1>
      <input
        value={name}
        onChange={e => setName(e.target.value)}
      />
      <button onClick={handleClick}>
        Insert
      </button>
      <ul>
        {artists.map(artist => (
          <li key={artist.id}>{artist.name}</li>
        ))}
      </ul>
    </>
  );
}
    

      import { useState } from 'react';

const initialList = [
  { id: 0, title: 'Big Bellies' },
  { id: 1, title: 'Lunar Landscape' },
  { id: 2, title: 'Terracotta Army' },
];

export default function List() {
  const [list, setList] = useState(initialList);

  function handleClick() {
    const nextList = [...list];
    nextList.reverse();
    setList(nextList);
  }

  return (
    <>
      <button onClick={handleClick}>
        Reverse
      </button>
      <ul>
        {list.map(artwork => (
          <li key={artwork.id}>{artwork.title}</li>
        ))}
      </ul>
    </>
  );
}
    

      const nextList = [...list];
nextList[0].seen = true; // تغییر مستقیم ویژگی آیتم اول
setList(nextList);
    

      import { useState } from 'react';

let nextId = 3;
const initialList = [
  { id: 0, title: 'Big Bellies', seen: false },
  { id: 1, title: 'Lunar Landscape', seen: false },
  { id: 2, title: 'Terracotta Army', seen: true },
];

export default function BucketList() {
  const [myList, setMyList] = useState(initialList);
  const [yourList, setYourList] = useState(
    initialList
  );

  function handleToggleMyList(artworkId, nextSeen) {
    const myNextList = [...myList];
    const artwork = myNextList.find(
      a => a.id === artworkId
    );
    artwork.seen = nextSeen;
    setMyList(myNextList);
  }

  function handleToggleYourList(artworkId, nextSeen) {
    const yourNextList = [...yourList];
    const artwork = yourNextList.find(
      a => a.id === artworkId
    );
    artwork.seen = nextSeen;
    setYourList(yourNextList);
  }

  return (
    <>
      <h1>Art Bucket List</h1>
      <h2>My list of art to see:</h2>
      <ItemList
        artworks={myList}
        onToggle={handleToggleMyList} />
      <h2>Your list of art to see:</h2>
      <ItemList
        artworks={yourList}
        onToggle={handleToggleYourList} />
    </>
  );
}

function ItemList({ artworks, onToggle }) {
  return (
    <ul>
      {artworks.map(artwork => (
        <li key={artwork.id}>
          <label>
            <input
              type="checkbox"
              checked={artwork.seen}
              onChange={e => {
                onToggle(
                  artwork.id,
                  e.target.checked
                );
              }}
            />
            {artwork.title}
          </label>
        </li>
      ))}
    </ul>
  );
}
    

      const myNextList = [...myList];
const artwork = myNextList.find(a => a.id === artworkId);
artwork.seen = nextSeen; // Problem: mutates an existing item
setMyList(myNextList);
    

      setMyList(myList.map(artwork => {
  if (artwork.id === artworkId) {
    // Create a *new* object with changes
    return { ...artwork, seen: nextSeen };
  } else {
    // No changes
    return artwork;
  }
}));
    

      import { useState } from 'react';

let nextId = 3;
const initialList = [
  { id: 0, title: 'Big Bellies', seen: false },
  { id: 1, title: 'Lunar Landscape', seen: false },
  { id: 2, title: 'Terracotta Army', seen: true },
];

export default function BucketList() {
  const [myList, setMyList] = useState(initialList);
  const [yourList, setYourList] = useState(
    initialList
  );

  function handleToggleMyList(artworkId, nextSeen) {
    setMyList(myList.map(artwork => {
      if (artwork.id === artworkId) {
        // Create a *new* object with changes
        return { ...artwork, seen: nextSeen };
      } else {
        // No changes
        return artwork;
      }
    }));
  }

  function handleToggleYourList(artworkId, nextSeen) {
    setYourList(yourList.map(artwork => {
      if (artwork.id === artworkId) {
        // Create a *new* object with changes
        return { ...artwork, seen: nextSeen };
      } else {
        // No changes
        return artwork;
      }
    }));
  }

  return (
    <>
      <h1>Art Bucket List</h1>
      <h2>My list of art to see:</h2>
      <ItemList
        artworks={myList}
        onToggle={handleToggleMyList} />
      <h2>Your list of art to see:</h2>
      <ItemList
        artworks={yourList}
        onToggle={handleToggleYourList} />
    </>
  );
}

function ItemList({ artworks, onToggle }) {
  return (
    <ul>
      {artworks.map(artwork => (
        <li key={artwork.id}>
          <label>
            <input
              type="checkbox"
              checked={artwork.seen}
              onChange={e => {
                onToggle(
                  artwork.id,
                  e.target.checked
                );
              }}
            />
            {artwork.title}
          </label>
        </li>
      ))}
    </ul>
  );
}
    

      import { useState } from 'react';
import { useImmer } from 'use-immer';

let nextId = 3;
const initialList = [
  { id: 0, title: 'Big Bellies', seen: false },
  { id: 1, title: 'Lunar Landscape', seen: false },
  { id: 2, title: 'Terracotta Army', seen: true },
];

export default function BucketList() {
  const [myList, updateMyList] = useImmer(
    initialList
  );
  const [yourList, updateYourList] = useImmer(
    initialList
  );

  function handleToggleMyList(id, nextSeen) {
    updateMyList(draft => {
      const artwork = draft.find(a =>
        a.id === id
      );
      artwork.seen = nextSeen;
    });
  }

  function handleToggleYourList(artworkId, nextSeen) {
    updateYourList(draft => {
      const artwork = draft.find(a =>
        a.id === artworkId
      );
      artwork.seen = nextSeen;
    });
  }

  return (
    <>
      <h1>Art Bucket List</h1>
      <h2>My list of art to see:</h2>
      <ItemList
        artworks={myList}
        onToggle={handleToggleMyList} />
      <h2>Your list of art to see:</h2>
      <ItemList
        artworks={yourList}
        onToggle={handleToggleYourList} />
    </>
  );
}

function ItemList({ artworks, onToggle }) {
  return (
    <ul>
      {artworks.map(artwork => (
        <li key={artwork.id}>
          <label>
            <input
              type="checkbox"
              checked={artwork.seen}
              onChange={e => {
                onToggle(
                  artwork.id,
                  e.target.checked
                );
              }}
            />
            {artwork.title}
          </label>
        </li>
      ))}
    </ul>
  );
}
    

      updateMyTodos(draft => {
  const artwork = draft.find(a => a.id === artworkId);
  artwork.seen = nextSeen;
});
    

      import { useState } from 'react';

const initialProducts = [{
  id: 0,
  name: 'Baklava',
  count: 1,
}, {
  id: 1,
  name: 'Cheese',
  count: 5,
}, {
  id: 2,
  name: 'Spaghetti',
  count: 2,
}];

export default function ShoppingCart() {
  const [
    products,
    setProducts
  ] = useState(initialProducts)

  function handleIncreaseClick(productId) {

  }

  return (
    <ul>
      {products.map(product => (
        <li key={product.id}>
          {product.name}
          {' '}
          (<b>{product.count}</b>)
          <button onClick={() => {
            handleIncreaseClick(product.id);
          }}>
            +
          </button>
        </li>
      ))}
    </ul>
  );
}
    

      import { useState } from 'react';

const initialProducts = [{
  id: 0,
  name: 'Baklava',
  count: 1,
}, {
  id: 1,
  name: 'Cheese',
  count: 5,
}, {
  id: 2,
  name: 'Spaghetti',
  count: 2,
}];

export default function ShoppingCart() {
  const [
    products,
    setProducts
  ] = useState(initialProducts)

  function handleIncreaseClick(productId) {
    setProducts(products.map(product => {
      if (product.id === productId) {
        return {
          ...product,
          count: product.count + 1
        };
      } else {
        return product;
      }
    }))
  }

  return (
    <ul>
      {products.map(product => (
        <li key={product.id}>
          {product.name}
          {' '}
          (<b>{product.count}</b>)
          <button onClick={() => {
            handleIncreaseClick(product.id);
          }}>
            +
          </button>
          <button>
            –
          </button>
        </li>
      ))}
    </ul>
  );
}
    

      import { useState } from 'react';
import AddTodo from './AddTodo.js';
import TaskList from './TaskList.js';

let nextId = 3;
const initialTodos = [
  { id: 0, title: 'Buy milk', done: true },
  { id: 1, title: 'Eat tacos', done: false },
  { id: 2, title: 'Brew tea', done: false },
];

export default function TaskApp() {
  const [todos, setTodos] = useState(
    initialTodos
  );

  function handleAddTodo(title) {
    todos.push({
      id: nextId++,
      title: title,
      done: false
    });
  }

  function handleChangeTodo(nextTodo) {
    const todo = todos.find(t =>
      t.id === nextTodo.id
    );
    todo.title = nextTodo.title;
    todo.done = nextTodo.done;
  }

  function handleDeleteTodo(todoId) {
    const index = todos.findIndex(t =>
      t.id === todoId
    );
    todos.splice(index, 1);
  }

  return (
    <>
      <AddTodo
        onAddTodo={handleAddTodo}
      />
      <TaskList
        todos={todos}
        onChangeTodo={handleChangeTodo}
        onDeleteTodo={handleDeleteTodo}
      />
    </>
  );
}
    

      import { useState } from 'react';
import { useImmer } from 'use-immer';
import AddTodo from './AddTodo.js';
import TaskList from './TaskList.js';

let nextId = 3;
const initialTodos = [
  { id: 0, title: 'Buy milk', done: true },
  { id: 1, title: 'Eat tacos', done: false },
  { id: 2, title: 'Brew tea', done: false },
];

export default function TaskApp() {
  const [todos, setTodos] = useState(
    initialTodos
  );

  function handleAddTodo(title) {
    todos.push({
      id: nextId++,
      title: title,
      done: false
    });
  }

  function handleChangeTodo(nextTodo) {
    const todo = todos.find(t =>
      t.id === nextTodo.id
    );
    todo.title = nextTodo.title;
    todo.done = nextTodo.done;
  }

  function handleDeleteTodo(todoId) {
    const index = todos.findIndex(t =>
      t.id === todoId
    );
    todos.splice(index, 1);
  }

  return (
    <>
      <AddTodo
        onAddTodo={handleAddTodo}
      />
      <TaskList
        todos={todos}
        onChangeTodo={handleChangeTodo}
        onDeleteTodo={handleDeleteTodo}
      />
    </>
  );
}
    

      import { useState } from 'react';

const initialProducts = [{
  id: 0,
  name: 'Baklava',
  count: 1,
}, {
  id: 1,
  name: 'Cheese',
  count: 5,
}, {
  id: 2,
  name: 'Spaghetti',
  count: 2,
}];

export default function ShoppingCart() {
  const [
    products,
    setProducts
  ] = useState(initialProducts)

  function handleIncreaseClick(productId) {
    setProducts(products.map(product => {
      if (product.id === productId) {
        return {
          ...product,
          count: product.count + 1
        };
      } else {
        return product;
      }
    }))
  }

  return (
    <ul>
      {products.map(product => (
        <li key={product.id}>
          {product.name}
          {' '}
          (<b>{product.count}</b>)
          <button onClick={() => {
            handleIncreaseClick(product.id);
          }}>
            +
          </button>
        </li>
      ))}
    </ul>
  );
}
    

      import { useState } from 'react';

const initialProducts = [{
  id: 0,
  name: 'Baklava',
  count: 1,
}, {
  id: 1,
  name: 'Cheese',
  count: 5,
}, {
  id: 2,
  name: 'Spaghetti',
  count: 2,
}];

export default function ShoppingCart() {
  const [
    products,
    setProducts
  ] = useState(initialProducts)

  function handleIncreaseClick(productId) {
    setProducts(products.map(product => {
      if (product.id === productId) {
        return {
          ...product,
          count: product.count + 1
        };
      } else {
        return product;
      }
    }))
  }

  function handleDecreaseClick(productId) {
    let nextProducts = products.map(product => {
      if (product.id === productId) {
        return {
          ...product,
          count: product.count - 1
        };
      } else {
        return product;
      }
    });
    nextProducts = nextProducts.filter(p =>
      p.count > 0
    );
    setProducts(nextProducts)
  }

  return (
    <ul>
      {products.map(product => (
        <li key={product.id}>
          {product.name}
          {' '}
          (<b>{product.count}</b>)
          <button onClick={() => {
            handleIncreaseClick(product.id);
          }}>
            +
          </button>
          <button onClick={() => {
            handleDecreaseClick(product.id);
          }}>
            –
          </button>
        </li>
      ))}
    </ul>
  );
}
    

      import { useState } from 'react';
import AddTodo from './AddTodo.js';
import TaskList from './TaskList.js';

let nextId = 3;
const initialTodos = [
  { id: 0, title: 'Buy milk', done: true },
  { id: 1, title: 'Eat tacos', done: false },
  { id: 2, title: 'Brew tea', done: false },
];

export default function TaskApp() {
  const [todos, setTodos] = useState(
    initialTodos
  );

  function handleAddTodo(title) {
    setTodos([
      ...todos,
      {
        id: nextId++,
        title: title,
        done: false
      }
    ]);
  }

  function handleChangeTodo(nextTodo) {
    setTodos(todos.map(t => {
      if (t.id === nextTodo.id) {
        return nextTodo;
      } else {
        return t;
      }
    }));
  }

  function handleDeleteTodo(todoId) {
    setTodos(
      todos.filter(t => t.id !== todoId)
    );
  }

  return (
    <>
      <AddTodo
        onAddTodo={handleAddTodo}
      />
      <TaskList
        todos={todos}
        onChangeTodo={handleChangeTodo}
        onDeleteTodo={handleDeleteTodo}
      />
    </>
  );
}
    

      import { useState } from 'react';
import { useImmer } from 'use-immer';
import AddTodo from './AddTodo.js';
import TaskList from './TaskList.js';

let nextId = 3;
const initialTodos = [
  { id: 0, title: 'Buy milk', done: true },
  { id: 1, title: 'Eat tacos', done: false },
  { id: 2, title: 'Brew tea', done: false },
];

export default function TaskApp() {
  const [todos, updateTodos] = useImmer(
    initialTodos
  );

  function handleAddTodo(title) {
    updateTodos(draft => {
      draft.push({
        id: nextId++,
        title: title,
        done: false
      });
    });
  }

  function handleChangeTodo(nextTodo) {
    updateTodos(draft => {
      const todo = draft.find(t =>
        t.id === nextTodo.id
      );
      todo.title = nextTodo.title;
      todo.done = nextTodo.done;
    });
  }

  function handleDeleteTodo(todoId) {
    updateTodos(draft => {
      const index = draft.findIndex(t =>
        t.id === todoId
      );
      draft.splice(index, 1);
    });
  }

  return (
    <>
      <AddTodo
        onAddTodo={handleAddTodo}
      />
      <TaskList
        todos={todos}
        onChangeTodo={handleChangeTodo}
        onDeleteTodo={handleDeleteTodo}
      />
    </>
  );
}
    

      import { useState } from 'react';
import { useImmer } from 'use-immer';
import AddTodo from './AddTodo.js';
import TaskList from './TaskList.js';

let nextId = 3;
const initialTodos = [
  { id: 0, title: 'Buy milk', done: true },
  { id: 1, title: 'Eat tacos', done: false },
  { id: 2, title: 'Brew tea', done: false },
];

export default function TaskApp() {
  const [todos, updateTodos] = useImmer(
    initialTodos
  );

  function handleAddTodo(title) {
    updateTodos(draft => {
      draft.push({
        id: nextId++,
        title: title,
        done: false
      });
    });
  }

  function handleChangeTodo(nextTodo) {
    updateTodos(todos.map(todo => {
      if (todo.id === nextTodo.id) {
        return nextTodo;
      } else {
        return todo;
      }
    }));
  }

  function handleDeleteTodo(todoId) {
    updateTodos(
      todos.filter(t => t.id !== todoId)
    );
  }

  return (
    <>
      <AddTodo
        onAddTodo={handleAddTodo}
      />
      <TaskList
        todos={todos}
        onChangeTodo={handleChangeTodo}
        onDeleteTodo={handleDeleteTodo}
      />
    </>
  );
}