<script src="https://connect.tencentcloud.com/sdk/tccc-user-call-sdk.umd.js?sdkAppId=your_sdkAppId&userId=your_userId"></script>
<script>
  const { createUser, TcccSipError, ErrorCode } = window.TcccUserCall;
</script>

async function start () {
    const sdkAppId = 20000000;
    const userId = 'xxx';
    const audioChannelId = 'xxx';
    
    // 1. Call the service provider's backend API to obtain the userSig.
    // Refer to the Node.js example in "Preliminary Preparation".
    const response = await fetch('https://example.api.com/genUserSig?userId=' + encodeURIComponent(userId), {
      method: 'GET',
    });
    
    if (!response.ok) {
      throw new Error(`HTTP error! Status code: ${response.status}`);
    }
    
    const { userSig } = await response.json();
 
    // 2. Create a user instance.
    const { createUser, TcccSipError, ErrorCode } = window.TcccUserCall;
    const user = createUser({
      sdkAppId,
      userId,
      userSig,
    });
    
    // 3. Listen for the ready event.
    user.on('ready', () => {
      console.log('SDK is ready. You can initiate a call.');
      // 5. Initiate an audio call (call this after the ready event is triggered).
      makeCall(audioChannelId)
    });
    
    // 4. Initialize (establish a connection).
    user.init();
   
    async function makeCall(audioChannelId) {
      try {
        const session = await user.startAudioCall(audioChannelId);
    
        session.on('progress', (event) => {
          const { status_code, reason_phrase } = event.response;
          if (status_code === 180 || status_code === 183) {
            console.log('The line is ringing.', reason_phrase);
          }
        });
    
        session.on('accepted', () => {
          console.log('The other party has answered the call.');
        });
    
        session.on('ended', (event) => {
          console.log('Call ended', event.cause);
        });
    
        session.on('failed', (event) => {
          console.error('Call failed', event.cause);
        });
      } catch (err) {
        if (err instanceof TcccSipError) {
          console.error('Call error [' + err.code + ']: ' + err.message);
        }
      }
    }
    
    // 6. When outbound calls are no longer needed (for example, when the page is terminated), call cleanup to release resources.
    async function cleanup() {
      await user.unInit();
    }
}

start();

const user = createUser({
  sdkAppId: 1400000000, // The type is number.
  userId: 'your_userId',
  userSig: 'your_userSig',
});

try {
  await user.startAudioCall('xxx');
} catch (err) {
  if (err.code === ErrorCode.User.InvalidUserSig) {
    user.updateUserSig('new userSig');
    // Initiate the call again after the update.
  }
}

try {
  const session = await user.startAudioCall('xxx');
} catch (err) {
  if (err.code === ErrorCode.User.CallInProgress) {
    console.error('A call is already in progress.');
  }
}

session.terminate();

await session.muteAudio(true);  // Mute the audio.
await session.muteAudio(false); // Unmute the audio.

await session.sendDTMFTone('1');
await session.sendDTMFTone('#');

const { audio } = session.isMuted();
console.log('Muted:', audio);

const { TcccSipError, ErrorCode } = window.TcccUserCall;

try {
  await user.startAudioCall('xxx');
} catch (err) {
  // Method 1: Use instanceof to check.
  if (err instanceof TcccSipError) {
    console.error(err.code, err.message);
  }

  // Method 2: Use ErrorCode constants for exact matching.
  if (err.code === ErrorCode.User.InvalidUserSig) {
    user.updateUserSig('new userSig');
  }

  // Method 3: View the complete error chain.
  if (err instanceof TcccSipError) {
    console.error(err.fullMessage);
  }
}