Build a workflow
Registering application logic as a step in a stateful workflow.
AI Agents · Function
add_node
Adds a named node to a LangGraph.js StateGraph. The node implementation runs when graph execution reaches it and can return updates to the graph state.
How it works
In the JavaScript graph builder, addNode registers a named node implementation in a StateGraph. The node can be a function that returns state updates; after adding edges, compile the builder and invoke the resulting graph.
Syntax
graph.addNode(name, node)Parameters
| Name | Type | Description |
|---|---|---|
name | string | The node name used to identify the node and reference it from edges. |
node | NodeAction | The node implementation that runs when the graph reaches this node. |
Returns
The StateGraph builder, enabling chained graph construction.
Key points
- The first argument identifies the node, while the second supplies the function or runnable that performs its work.
- Create the graph with a state schema before adding nodes.
- Connect START to the registered node so execution can enter it.
Example: Register a node in a StateGraph
import { Annotation, StateGraph, START, END } from "@langchain/langgraph";
const State = Annotation.Root({
result: Annotation<string>(),
});
const node = () => ({ result: "done" });
const graph = new StateGraph(State)
.addNode("node", node)
.addEdge(START, "node")
.addEdge("node", END)
.compile();
console.log(await graph.invoke({}));Defines a state graph, registers a node by name, connects it between START and END, compiles the graph, and invokes it.
When to use it
Add agent steps
Connecting an agent or tool operation to graph control flow.
Compose subgraphs
Embedding a compiled subgraph when state keys are shared.
Related
StateGraphaddEdgeSTARTcompileinvoke