Type Alias NodeHandler

NodeHandler: (
state: Readonly<GraphState>,
ctx?: NodeContext,
) => Promise<NodeReturn>

Handler function for a graph node. Receives current state and an optional per-run context, returns either:

Partial<GraphState> (legacy, common case) — merged via reducers
Command — update portion is merged via reducers
Interrupt — pauses the graph; emits checkpoint with interrupt metadata

The ctx parameter is optional — pre-#1895 handlers that take only state remain valid (additive widening).

Type Declaration

- (state: Readonly<GraphState>, ctx?: NodeContext): Promise<NodeReturn>
- Parameters
  - state: Readonly<GraphState>
  - Optionalctx: NodeContext
  Returns Promise<NodeReturn>