@langchain/anthropic/dist/utils/stream_events.cjs.map

Anthropic integrations for LangChain.js

{"version":3,"file":"stream_events.cjs","names":[],"sources":["../../src/utils/stream_events.ts"],"sourcesContent":["/**\n * Converts a raw Anthropic SSE event stream into LangChain ChatModelStreamEvents.\n *\n * @module\n */\n\nimport type Anthropic from \"@anthropic-ai/sdk\";\nimport type {\n  ChatModelStreamEvent,\n  ContentBlockDelta,\n  FinishReason,\n} from \"@langchain/core/language_models/event\";\nimport type { ContentBlock } from \"@langchain/core/messages/content\";\nimport type { UsageMetadata } from \"@langchain/core/messages/metadata\";\nimport type { AnthropicMessageStreamEvent } from \"../types.js\";\n\n// ─── Public API ─────────────────────────────────────────────────\n\nexport interface ConvertAnthropicStreamOptions {\n  streamUsage?: boolean;\n}\n\n/**\n * Convert an async iterable of raw Anthropic stream events into\n * LangChain `ChatModelStreamEvent`s with typed deltas.\n */\nexport async function* convertAnthropicStream(\n  source: AsyncIterable<AnthropicMessageStreamEvent>,\n  options: ConvertAnthropicStreamOptions = {}\n): AsyncGenerator<ChatModelStreamEvent> {\n  const shouldStreamUsage = options.streamUsage ?? true;\n\n  // Track accumulated state per content block (for finalization)\n  const blockAccumulators = new Map<\n    number,\n    // oxlint-disable-next-line @typescript-eslint/no-explicit-any\n    Record<string, any>\n  >();\n  let usageSnapshot: UsageMetadata | undefined;\n  let stopReason: string | null = null;\n\n  for await (const data of source) {\n    switch (data.type) {\n      // ── Message lifecycle ──────────────────────────────────\n      case \"message_start\": {\n        const { usage, id, model } = data.message;\n        if (usage && shouldStreamUsage) {\n          usageSnapshot = buildUsageSnapshot(usage);\n        }\n        yield {\n          event: \"message-start\" as const,\n          id,\n          ...(usageSnapshot ? { usage: usageSnapshot } : {}),\n        };\n        yield {\n          event: \"provider\" as const,\n          provider: \"anthropic\",\n          name: \"message_start\",\n          payload: { model, id },\n        };\n        break;\n      }\n\n      case \"message_delta\": {\n        stopReason = data.delta.stop_reason;\n        if (shouldStreamUsage && data.usage) {\n          if (!usageSnapshot) {\n            usageSnapshot = {\n              input_tokens: 0,\n              output_tokens: data.usage.output_tokens,\n              total_tokens: data.usage.output_tokens,\n            };\n          } else {\n            usageSnapshot = {\n              ...usageSnapshot,\n              output_tokens:\n                usageSnapshot.output_tokens + data.usage.output_tokens,\n              total_tokens:\n                usageSnapshot.input_tokens +\n                usageSnapshot.output_tokens +\n                data.usage.output_tokens,\n            };\n          }\n          yield { event: \"usage\" as const, usage: usageSnapshot };\n        }\n        if (\n          \"context_management\" in data.delta &&\n          data.delta.context_management\n        ) {\n          yield {\n            event: \"provider\" as const,\n            provider: \"anthropic\",\n            name: \"context_management\",\n            payload: data.delta.context_management,\n          };\n        }\n        break;\n      }\n\n      case \"message_stop\": {\n        yield {\n          event: \"message-finish\" as const,\n          reason: mapStopReason(stopReason),\n          ...(usageSnapshot ? { usage: usageSnapshot } : {}),\n          metadata: { model_provider: \"anthropic\" },\n        };\n        break;\n      }\n\n      // ── Content block lifecycle ───────────────────────────\n      case \"content_block_start\": {\n        const { index, content_block } = data;\n        const mapped = mapBlockToContentBlock(content_block, index);\n        blockAccumulators.set(index, { ...mapped });\n        yield {\n          event: \"content-block-start\" as const,\n          index,\n          content: mapped,\n        };\n        break;\n      }\n\n      case \"content_block_delta\": {\n        const { index, delta } = data;\n        const acc = blockAccumulators.get(index);\n        if (!acc) break;\n\n        const { contentDelta, accumulated } = applyAnthropicDelta(acc, delta);\n        blockAccumulators.set(index, accumulated);\n\n        yield {\n          event: \"content-block-delta\" as const,\n          index,\n          delta: contentDelta,\n        };\n        break;\n      }\n\n      case \"content_block_stop\": {\n        const { index } = data;\n        const acc = blockAccumulators.get(index);\n        if (!acc) break;\n\n        const finalized = finalizeBlock(acc);\n        yield {\n          event: \"content-block-finish\" as const,\n          index,\n          content: finalized,\n        };\n        blockAccumulators.delete(index);\n        break;\n      }\n\n      // ── Unhandled → provider passthrough ───────────────────\n      default: {\n        yield {\n          event: \"provider\" as const,\n          provider: \"anthropic\",\n          name: data.type,\n          payload: data,\n        };\n        break;\n      }\n    }\n  }\n}\n\n// ─── Internal helpers ───────────────────────────────────────────\n\nfunction mapStopReason(stopReason: string | null | undefined): FinishReason {\n  switch (stopReason) {\n    case \"end_turn\":\n    case \"stop_sequence\":\n      return \"stop\";\n    case \"tool_use\":\n      return \"tool_use\";\n    case \"max_tokens\":\n      return \"length\";\n    default:\n      return \"stop\";\n  }\n}\n\nfunction buildUsageSnapshot(\n  usage: Anthropic.Messages.Usage | Record<string, number>\n): UsageMetadata {\n  const cacheCreation =\n    (usage as Record<string, number>).cache_creation_input_tokens ?? 0;\n  const cacheRead =\n    (usage as Record<string, number>).cache_read_input_tokens ?? 0;\n  const totalInput = usage.input_tokens + cacheCreation + cacheRead;\n  return {\n    input_tokens: totalInput,\n    output_tokens: usage.output_tokens,\n    total_tokens: totalInput + usage.output_tokens,\n    input_token_details: {\n      cache_creation: cacheCreation,\n      cache_read: cacheRead,\n    },\n  };\n}\n\nfunction mapBlockToContentBlock(\n  // oxlint-disable-next-line @typescript-eslint/no-explicit-any\n  block: any,\n  index: number\n  // oxlint-disable-next-line @typescript-eslint/no-explicit-any\n): Record<string, any> {\n  switch (block.type) {\n    case \"text\":\n      return { type: \"text\" as const, text: block.text ?? \"\", index };\n    case \"thinking\":\n      return {\n        type: \"reasoning\" as const,\n        reasoning: block.thinking ?? \"\",\n        index,\n      };\n    case \"redacted_thinking\":\n      return { type: \"non_standard\" as const, value: { ...block }, index };\n    case \"tool_use\":\n      return {\n        type: \"tool_call_chunk\" as const,\n        id: block.id,\n        name: block.name,\n        args: \"\",\n        index,\n      };\n    case \"server_tool_use\":\n      return {\n        type: \"server_tool_call_chunk\" as const,\n        id: block.id,\n        name: block.name,\n        args: \"\",\n        index,\n      };\n    default:\n      return { type: \"non_standard\" as const, value: { ...block }, index };\n  }\n}\n\n/**\n * Map an Anthropic content_block_delta to a content block delta\n * and update the accumulated state.\n */\nfunction applyAnthropicDelta(\n  // oxlint-disable-next-line @typescript-eslint/no-explicit-any\n  accumulated: Record<string, any>,\n  // oxlint-disable-next-line @typescript-eslint/no-explicit-any\n  delta: any\n): {\n  contentDelta: ContentBlockDelta;\n  // oxlint-disable-next-line @typescript-eslint/no-explicit-any\n  accumulated: Record<string, any>;\n} {\n  switch (delta.type) {\n    case \"text_delta\":\n      return {\n        contentDelta: { type: \"text-delta\" as const, text: delta.text },\n        accumulated: {\n          ...accumulated,\n          text: (accumulated.text ?? \"\") + delta.text,\n        },\n      };\n\n    case \"thinking_delta\":\n      return {\n        contentDelta: {\n          type: \"reasoning-delta\" as const,\n          reasoning: delta.thinking,\n        },\n        accumulated: {\n          ...accumulated,\n          reasoning: (accumulated.reasoning ?? \"\") + delta.thinking,\n        },\n      };\n\n    case \"input_json_delta\": {\n      const newArgs = (accumulated.args ?? \"\") + delta.partial_json;\n      return {\n        contentDelta: {\n          type: \"block-delta\" as const,\n          fields: { type: accumulated.type, args: newArgs },\n        },\n        accumulated: { ...accumulated, args: newArgs },\n      };\n    }\n\n    case \"citations_delta\": {\n      const annotations = [...(accumulated.annotations ?? []), delta.citation];\n      return {\n        contentDelta: {\n          type: \"block-delta\" as const,\n          fields: {\n            type: accumulated.type,\n            annotations,\n          },\n        },\n        accumulated: {\n          ...accumulated,\n          annotations,\n        },\n      };\n    }\n\n    case \"signature_delta\":\n      return {\n        contentDelta: {\n          type: \"block-delta\" as const,\n          fields: { type: accumulated.type, signature: delta.signature },\n        },\n        accumulated: { ...accumulated, signature: delta.signature },\n      };\n\n    case \"compaction_delta\":\n      return {\n        contentDelta: {\n          type: \"block-delta\" as const,\n          fields: {\n            type: \"non_standard\",\n            value: { ...(accumulated.value ?? {}), compaction: delta },\n          },\n        },\n        accumulated: {\n          ...accumulated,\n          value: { ...(accumulated.value ?? {}), compaction: delta },\n        },\n      };\n\n    default:\n      return {\n        contentDelta: {\n          type: \"block-delta\" as const,\n          fields: { type: accumulated.type, ...delta },\n        },\n        accumulated,\n      };\n  }\n}\n\nfunction finalizeBlock(\n  // oxlint-disable-next-line @typescript-eslint/no-explicit-any\n  accumulated: Record<string, any>\n): ContentBlock {\n  if (\n    accumulated.type === \"tool_call_chunk\" ||\n    accumulated.type === \"server_tool_call_chunk\"\n  ) {\n    const finalType =\n      accumulated.type === \"tool_call_chunk\"\n        ? 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