Function handleTextPart

packages/ai-opencode/src/stream/translate.ts:189–226

(
    part: Extract<OpencodePart, { type: 'text' }>,
    delta: string | undefined,
  )

  }

  function* handleTextPart(
    part: Extract<OpencodePart, { type: 'text' }>,
    delta: string | undefined,
  ): Generator<StreamChunk> {
    yield* closeReasoning()

    const prev = textAccumulators.get(part.id) ?? ''
    let deltaText: string
    if (typeof delta === 'string' && delta !== '') {
      deltaText = delta
      textAccumulators.set(part.id, prev + delta)
    } else {
      const full = part.text
      deltaText = full.startsWith(prev) ? full.slice(prev.length) : full
      textAccumulators.set(part.id, full)
    }
    if (deltaText === '') return

    if (openTextId !== part.id) {
      yield* closeText()
      openTextId = part.id
      yield {
        type: EventType.TEXT_MESSAGE_START,
        messageId: part.id,
        model,
        timestamp: now(),
        role: 'assistant',
      }
    }
    yield {
      type: EventType.TEXT_MESSAGE_CONTENT,
      messageId: part.id,
      model,
      timestamp: now(),
      delta: deltaText,
      content: textAccumulators.get(part.id) ?? deltaText,
    }
  }

  function* handleReasoningPart(
    part: Extract<OpencodePart, { type: 'reasoning' }>,