自定义流式输出

from typing import TypedDict
from langgraph.config import get_stream_writer

class State(TypedDict):
	placeholder: str

def node(state: State):
    # 创建写入流
	writer = get_stream_writer()
	
    # 定制流式输出
	items = ["books", "penciles", "pictures"]
	for chunk in items:
		writer({ "custom_data": chunk })

  	return { "placeholder": ",".join(items) }

graph = (
  StateGraph(State)
    .add_node(node)
    .add_edge(START, "node")
    .compile()
)

# 使用custom输出
for chunk in graph.stream({}, stream_mode="custom"):
 	print(chunk)