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Triggered for each incremental text chunk as the AI generates its response. This event is sent multiple times during response generation. Handle this event to display AI responses in real-time as they’re generated.

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Event Properties

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type
string
Event type. Always "realtime.response.audio_transcript.delta" for this event.
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data
object
Event data object containing response information.
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data.content
string
The new text chunk to append to the accumulated response.Example: "Hello there"
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data.id
string
Unique identifier for this response. Used to track concurrent responses.Example: "resp-123456"
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data.response_id
string
Alternative field name for the response ID. May be present for compatibility.Example: "resp-123456"
{
  "type": "realtime.response.audio_transcript.delta",
  "data": {
    "content": "Hello there",
    "id": "resp-123456"
  }
}

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Usage Example

const NavTalkMessageType = Object.freeze({
    REALTIME_RESPONSE_AUDIO_TRANSCRIPT_DELTA: "realtime.response.audio_transcript.delta",
    // ... other event types
});

let markdownBuffer = new Map();
let responseSpans = new Map();

async function handleReceivedMessage(data) {
    const nav_data = data.data;
    
    switch (data.type) {
        case NavTalkMessageType.REALTIME_RESPONSE_AUDIO_TRANSCRIPT_DELTA:
            const transcript = nav_data.content;
            const responseId = nav_data.id;
            
            // Accumulate content by response ID
            if (!markdownBuffer.has(responseId)) {
                markdownBuffer.set(responseId, "");
            }
            const existingBuffer = markdownBuffer.get(responseId);
            markdownBuffer.set(responseId, existingBuffer + transcript);
            
            // Get or create message element
            let aiMessageSpan = responseSpans.get(responseId);
            if (!aiMessageSpan) {
                // Create new message element
                aiMessageSpan = createMessageElement();
                responseSpans.set(responseId, aiMessageSpan);
            }
            
            // Update displayed content
            const fullContent = markdownBuffer.get(responseId);
            aiMessageSpan.innerHTML = marked.parse(fullContent);
            break;
    }
}