# IVS 聊天用戶端傳訊 SDK：React 和 React Native 最佳實務
<a name="chat-sdk-react-best-practices"></a>

本文件說明使用 React and React Native 的 Amazon IVS 聊天功能傳訊 SDK 最重要的實務。此資訊應可讓您在 React 應用程式中建立典型聊天功能，並讓您了解深入探索 IVS 聊天功能傳訊 SDK 進階部分所需的背景知識。

## 建立聊天室初始化程式勾點
<a name="chatroom-initializer-hook"></a>

`ChatRoom` 類別包含核心聊天方法和接聽程式，用於管理連線狀態和接聽諸如已接收訊息或已刪除訊息之類的事件。我們會在這裡展示如何在勾點中正確儲存聊天執行個體。

### 實作
<a name="chatroom-initializer-hook-implementation"></a>

------
#### [ TypeScript ]

```
// useChatRoom.ts

import React from 'react';
import { ChatRoom, ChatRoomConfig } from 'amazon-ivs-chat-messaging';

export const useChatRoom = (config: ChatRoomConfig) => {
  const [room] = React.useState(() => new ChatRoom(config));

  return { room };
};
```

------
#### [ JavaScript ]

```
import React from 'react';
import { ChatRoom } from 'amazon-ivs-chat-messaging';

export const useChatRoom = (config) => {
  const [room] = React.useState(() => new ChatRoom(config));

  return { room };
};
```

------

注意：我們不會使用 `setState` 勾點的 `dispatch` 方法，因為您無法即時更新組態參數。SDK 可建立一次執行個體，但無法更新字符提供者。

**重要事項**：請使用一次 `ChatRoom` 初始化程式勾點，以初始化新的聊天室執行個體。

### 範例
<a name="chatroom-initializer-hook-example"></a>

**TypeScript/JavaScript**：

```
// ...

const MyChatScreen = () => {
  const userId = 'Mike';
  const { room } = useChatRoom({
    regionOrUrl: SOCKET_URL,
    tokenProvider: () => tokenProvider(ROOM_ID, ['SEND_MESSAGE']),
  });

  const handleConnect = () => {
    room.connect();
  };

  // ...
};

// ...
```

### 接聽連線狀態
<a name="chatroom-initializer-hook-connection-state"></a>

您也可以在聊天室勾點中訂閱連線狀態更新。

#### 實作
<a name="connection-state-implementation"></a>

------
#### [ TypeScript ]

```
// useChatRoom.ts

import React from 'react';
import { ChatRoom, ChatRoomConfig, ConnectionState } from 'amazon-ivs-chat-messaging';

export const useChatRoom = (config: ChatRoomConfig) => {
  const [room] = useState(() => new ChatRoom(config));

  const [state, setState] = React.useState<ConnectionState>('disconnected');

  React.useEffect(() => {
    const unsubscribeOnConnecting = room.addListener('connecting', () => {
      setState('connecting');
    });

    const unsubscribeOnConnected = room.addListener('connect', () => {
      setState('connected');
    });

    const unsubscribeOnDisconnected = room.addListener('disconnect', () => {
      setState('disconnected');
    });

    return () => {
      unsubscribeOnConnecting();
      unsubscribeOnConnected();
      unsubscribeOnDisconnected();
    };
  }, []);

  return { room, state };
};
```

------
#### [ JavaScript ]

```
// useChatRoom.js

import React from 'react';
import { ChatRoom } from 'amazon-ivs-chat-messaging';

export const useChatRoom = (config) => {
  const [room] = useState(() => new ChatRoom(config));

  const [state, setState] = React.useState('disconnected');

  React.useEffect(() => {
    const unsubscribeOnConnecting = room.addListener('connecting', () => {
      setState('connecting');
    });

    const unsubscribeOnConnected = room.addListener('connect', () => {
      setState('connected');
    });

    const unsubscribeOnDisconnected = room.addListener('disconnect', () => {
      setState('disconnected');
    });

    return () => {
      unsubscribeOnConnecting();
      unsubscribeOnConnected();
      unsubscribeOnDisconnected();
    };
  }, []);

  return { room, state };
};
```

------

## 聊天室執行個體提供者
<a name="chatroom-instance-provider"></a>

若要在其他元件中使用勾點 (以避免屬性鑽研)，您可以使用 React `context` 建立聊天室提供者。

### 實作
<a name="chatroom-instance-provider-implementation"></a>

------
#### [ TypeScript ]

```
// ChatRoomContext.tsx

import React from 'react';
import { ChatRoom } from 'amazon-ivs-chat-messaging';

const ChatRoomContext = React.createContext<ChatRoom | undefined>(undefined);

export const useChatRoomContext = () => {
  const context = React.useContext(ChatRoomContext);

  if (context === undefined) {
    throw new Error('useChatRoomContext must be within ChatRoomProvider');
  }

  return context;
};

export const ChatRoomProvider = ChatRoomContext.Provider;
```

------
#### [ JavaScript ]

```
// ChatRoomContext.jsx

import React from 'react';
import { ChatRoom } from 'amazon-ivs-chat-messaging';

const ChatRoomContext = React.createContext(undefined);

export const useChatRoomContext = () => {
  const context = React.useContext(ChatRoomContext);

  if (context === undefined) {
    throw new Error('useChatRoomContext must be within ChatRoomProvider');
  }

  return context;
};

export const ChatRoomProvider = ChatRoomContext.Provider;
```

------

### 範例
<a name="chatroom-instance-provider-example"></a>

建立 `ChatRoomProvider` 後，您可以透過 `useChatRoomContext` 使用執行個體。

**重要事項**：請只在您需要存取聊天畫面和中間其他元件之間的 `context` 時，才將提供者放在根層級，以避免接聽連線時不必要的重新渲染。否則，請將提供者放在盡可能靠近聊天畫面的位置。

**TypeScript/JavaScript**：

```
// AppContainer

const AppContainer = () => {
  const { room } = useChatRoom({
    regionOrUrl: SOCKET_URL,
    tokenProvider: () => tokenProvider(ROOM_ID, ['SEND_MESSAGE']),
  });

  return (
    <ChatRoomProvider value={room}>
      <MyChatScreen />
    </ChatRoomProvider>
  );
};

// MyChatScreen

const MyChatScreen = () => {
  const room = useChatRoomContext();

  const handleConnect = () => {
    room.connect();
  };
  // ...
};

// ...
```

## 建立訊息接聽程式
<a name="message-listener"></a>

若要了解所有傳入訊息的最新資訊，您應訂閱 `message` 和 `deleteMessage` 事件。以下是幾個為元件提供聊天訊息的程式碼。

**重要事項**：為了提高效能，我們將 `ChatMessageContext` 從 `ChatRoomProvider` 分離出來，以免聊天訊息接聽程式在更新訊息狀態時發生多次重新渲染。請記得將 `ChatMessageContext` 套用至您會使用 `ChatMessageProvider` 的元件。

### 實作
<a name="message-listener-implementation"></a>

------
#### [ TypeScript ]

```
// ChatMessagesContext.tsx

import React from 'react';
import { ChatMessage } from 'amazon-ivs-chat-messaging';
import { useChatRoomContext } from './ChatRoomContext';

const ChatMessagesContext = React.createContext<ChatMessage[] | undefined>(undefined);

export const useChatMessagesContext = () => {
  const context = React.useContext(ChatMessagesContext);

  if (context === undefined) {
    throw new Error('useChatMessagesContext must be within ChatMessagesProvider);
  }

  return context;
};

export const ChatMessagesProvider = ({ children }: { children: React.ReactNode }) => {
  const room = useChatRoomContext();

  const [messages, setMessages] = React.useState<ChatMessage[]>([]);

  React.useEffect(() => {
    const unsubscribeOnMessageReceived = room.addListener('message', (message) => {
      setMessages((msgs) => [message, ...msgs]);
    });

    const unsubscribeOnMessageDeleted = room.addListener('messageDelete', (deleteEvent) => {
      setMessages((prev) => prev.filter((message) => message.id !== deleteEvent.messageId));
    });

    return () => {
      unsubscribeOnMessageDeleted();
      unsubscribeOnMessageReceived();
    };
  }, [room]);

  return <ChatMessagesContext.Provider value={messages}>{children}</ChatMessagesContext.Provider>;
};
```

------
#### [ JavaScript ]

```
// ChatMessagesContext.jsx

import React from 'react';
import { useChatRoomContext } from './ChatRoomContext';

const ChatMessagesContext = React.createContext(undefined);

export const useChatMessagesContext = () => {
  const context = React.useContext(ChatMessagesContext);

  if (context === undefined) {
    throw new Error('useChatMessagesContext must be within ChatMessagesProvider);
  }

  return context;
};

export const ChatMessagesProvider = ({ children }) => {
  const room = useChatRoomContext();

  const [messages, setMessages] = React.useState([]);

  React.useEffect(() => {
    const unsubscribeOnMessageReceived = room.addListener('message', (message) => {
      setMessages((msgs) => [message, ...msgs]);
    });

    const unsubscribeOnMessageDeleted = room.addListener('messageDelete', (deleteEvent) => {
      setMessages((prev) => prev.filter((message) => message.id !== deleteEvent.messageId));
    });

    return () => {
      unsubscribeOnMessageDeleted();
      unsubscribeOnMessageReceived();
    };
  }, [room]);

  return <ChatMessagesContext.Provider value={messages}>{children}</ChatMessagesContext.Provider>;
};
```

------

### React 中的範例
<a name="message-listener-example-react"></a>

**重要事項**：請記得以 `ChatMessagesProvider` 包裝您的訊息容器。`Message` 列是用於顯示訊息內容的範例元件。

**TypeScript/JavaScript**：

```
// your message list component...

import React from 'react';
import { useChatMessagesContext } from './ChatMessagesContext';

const MessageListContainer = () => {
  const messages = useChatMessagesContext();

  return (
    <React.Fragment>
      {messages.map((message) => (
        <MessageRow message={message} />
      ))}
    </React.Fragment>
  );
};
```

### React Native 中的範例
<a name="message-listener-example-react-native"></a>

根據預設，`ChatMessage` 包含 `id`，以自動作為每列中 `FlatList` 的 React金鑰；因此您不需要傳遞 `keyExtractor`。

------
#### [ TypeScript ]

```
// MessageListContainer.tsx

import React from 'react';
import { ListRenderItemInfo, FlatList } from 'react-native';
import { ChatMessage } from 'amazon-ivs-chat-messaging';
import { useChatMessagesContext } from './ChatMessagesContext';

const MessageListContainer = () => {
  const messages = useChatMessagesContext();

  const renderItem = useCallback(({ item }: ListRenderItemInfo<ChatMessage>) => <MessageRow />, []);

  return <FlatList data={messages} renderItem={renderItem} />;
};
```

------
#### [ JavaScript ]

```
// MessageListContainer.jsx

import React from 'react';
import { FlatList } from 'react-native';
import { useChatMessagesContext } from './ChatMessagesContext';

const MessageListContainer = () => {
  const messages = useChatMessagesContext();

  const renderItem = useCallback(({ item }) => <MessageRow />, []);

  return <FlatList data={messages} renderItem={renderItem} />;
};
```

------

## 應用程式中的多個聊天室執行個體
<a name="multiple-chatroom-instances"></a>

如果您在應用程式中使用多個並行聊天室，建議您為每個聊天建立各自的提供者，並將其用於聊天提供者。在此範例中，我們建立了 Help Bot 和 Customer Help 聊天。我們為兩者都建立了提供者。

------
#### [ TypeScript ]

```
// SupportChatProvider.tsx

import React from 'react';
import { SUPPORT_ROOM_ID, SOCKET_URL } from '../../config';
import { tokenProvider } from '../tokenProvider';
import { ChatRoomProvider } from './ChatRoomContext';
import { useChatRoom } from './useChatRoom';

export const SupportChatProvider = ({ children }: { children: React.ReactNode }) => {
  const { room } = useChatRoom({
    regionOrUrl: SOCKET_URL,
    tokenProvider: () => tokenProvider(SUPPORT_ROOM_ID, ['SEND_MESSAGE']),
  });

  return <ChatRoomProvider value={room}>{children}</ChatRoomProvider>;
};

// SalesChatProvider.tsx

import React from 'react';
import { SALES_ROOM_ID, SOCKET_URL } from '../../config';
import { tokenProvider } from '../tokenProvider';
import { ChatRoomProvider } from './ChatRoomContext';
import { useChatRoom } from './useChatRoom';

export const SalesChatProvider = ({ children }: { children: React.ReactNode }) => {
  const { room } = useChatRoom({
    regionOrUrl: SOCKET_URL,
    tokenProvider: () => tokenProvider(SALES_ROOM_ID, ['SEND_MESSAGE']),
  });

  return <ChatRoomProvider value={room}>{children}</ChatRoomProvider>;
};
```

------
#### [ JavaScript ]

```
// SupportChatProvider.jsx

import React from 'react';
import { SUPPORT_ROOM_ID, SOCKET_URL } from '../../config';
import { tokenProvider } from '../tokenProvider';
import { ChatRoomProvider } from './ChatRoomContext';
import { useChatRoom } from './useChatRoom';

export const SupportChatProvider = ({ children }) => {
  const { room } = useChatRoom({
    regionOrUrl: SOCKET_URL,
    tokenProvider: () => tokenProvider(SUPPORT_ROOM_ID, ['SEND_MESSAGE']),
  });

  return <ChatRoomProvider value={room}>{children}</ChatRoomProvider>;
};

// SalesChatProvider.jsx

import React from 'react';
import { SALES_ROOM_ID, SOCKET_URL } from '../../config';
import { tokenProvider } from '../tokenProvider';
import { ChatRoomProvider } from './ChatRoomContext';
import { useChatRoom } from './useChatRoom';

export const SalesChatProvider = ({ children }) => {
  const { room } = useChatRoom({
    regionOrUrl: SOCKET_URL,
    tokenProvider: () => tokenProvider(SALES_ROOM_ID, ['SEND_MESSAGE']),
  });

  return <ChatRoomProvider value={room}>{children}</ChatRoomProvider>;
};
```

------

### React 中的範例
<a name="multiple-chatroom-instances-example-react"></a>

現在您可以運用使用相同 `ChatRoomProvider` 的不同聊天提供者。稍後，您可以在每個畫面/檢視中重複使用相同的 `useChatRoomContext`。

**TypeScript/JavaScript**：

```
// App.tsx / App.jsx

const App = () => {
  return (
    <Routes>
      <Route
        element={
          <SupportChatProvider>
            <SupportChatScreen />
          </SupportChatProvider>
        }
      />
      <Route
        element={
          <SalesChatProvider>
            <SalesChatScreen />
          </SalesChatProvider>
        }
      />
    </Routes>
  );
};
```

### React Native 中的範例
<a name="multiple-chatroom-instances-example-react-native"></a>

**TypeScript/JavaScript**：

```
// App.tsx / App.jsx

const App = () => {
  return (
    <Stack.Navigator>
      <Stack.Screen name="SupportChat">
        <SupportChatProvider>
          <SupportChatScreen />
        </SupportChatProvider>
      </Stack.Screen>
      <Stack.Screen name="SalesChat">
        <SalesChatProvider>
          <SalesChatScreen />
        </SalesChatProvider>
      </Stack.Screen>
    </Stack.Navigator>
  );
};
```

**TypeScript/JavaScript**：

```
// SupportChatScreen.tsx / SupportChatScreen.jsx

// ...

const SupportChatScreen = () => {
  const room = useChatRoomContext();

  const handleConnect = () => {
    room.connect();
  };

  return (
    <>
      <Button title="Connect" onPress={handleConnect} />
      <MessageListContainer />
    </>
  );
};

// SalesChatScreen.tsx / SalesChatScreen.jsx

// ...

const SalesChatScreen = () => {
  const room = useChatRoomContext();

  const handleConnect = () => {
    room.connect();
  };

  return (
    <>
      <Button title="Connect" onPress={handleConnect} />
      <MessageListContainer />
    </>
  );
};
```