core[patch]: Expose graph endpoint from core (#5979)

* Expose graph endpoint from core

* Add exports

* Update extend method

* Allow adding conditional edges

* Fix

Author: jacoblee93

langchain-core/.gitignore

@@ -102,6 +102,10 @@ runnables.cjs
 runnables.js
 runnables.d.ts
 runnables.d.cts
+runnables/graph.cjs
+runnables/graph.js
+runnables/graph.d.ts
+runnables/graph.d.cts
 runnables/remote.cjs
 runnables/remote.js
 runnables/remote.d.ts

langchain-core/langchain.config.js

@@ -38,6 +38,7 @@ export const config = {
     prompts: "prompts/index",
     prompt_values: "prompt_values",
     runnables: "runnables/index",
+    "runnables/graph": "runnables/graph",
     "runnables/remote": "runnables/remote",
     retrievers: "retrievers/index",
     "retrievers/document_compressors": "retrievers/document_compressors/base",

langchain-core/package.json

@@ -329,6 +329,15 @@
       "import": "./runnables.js",
       "require": "./runnables.cjs"
     },
+    "./runnables/graph": {
+      "types": {
+        "import": "./runnables/graph.d.ts",
+        "require": "./runnables/graph.d.cts",
+        "default": "./runnables/graph.d.ts"
+      },
+      "import": "./runnables/graph.js",
+      "require": "./runnables/graph.cjs"
+    },
     "./runnables/remote": {
       "types": {
         "import": "./runnables/remote.d.ts",
@@ -698,6 +707,10 @@
     "runnables.js",
     "runnables.d.ts",
     "runnables.d.cts",
+    "runnables/graph.cjs",
+    "runnables/graph.js",
+    "runnables/graph.d.ts",
+    "runnables/graph.d.cts",
     "runnables/remote.cjs",
     "runnables/remote.js",
     "runnables/remote.d.ts",

langchain-core/src/runnables/graph.ts

@@ -11,7 +11,9 @@ import { drawMermaid, drawMermaidPng } from "./graph_mermaid.js";
 
 const MAX_DATA_DISPLAY_NAME_LENGTH = 42;
 
-export function nodeDataStr(node: Node): string {
+export { Node, Edge };
+
+function nodeDataStr(node: Node): string {
   if (!isUuid(node.id)) {
     return node.id;
   } else if (isRunnableInterface(node.data)) {
@@ -101,14 +103,24 @@ export class Graph {
     );
   }
 
-  addEdge(source: Node, target: Node, data?: string): Edge {
+  addEdge(
+    source: Node,
+    target: Node,
+    data?: string,
+    conditional?: boolean
+  ): Edge {
     if (this.nodes[source.id] === undefined) {
       throw new Error(`Source node ${source.id} not in graph`);
     }
     if (this.nodes[target.id] === undefined) {
       throw new Error(`Target node ${target.id} not in graph`);
     }
-    const edge: Edge = { source: source.id, target: target.id, data };
+    const edge: Edge = {
+      source: source.id,
+      target: target.id,
+      data,
+      conditional,
+    };
     this.edges.push(edge);
     return edge;
   }
@@ -135,14 +147,40 @@ export class Graph {
     return found[0];
   }
 
-  extend(graph: Graph): void {
-    // Add all nodes from the other graph, taking care to avoid duplicates
+  /**
+   * Add all nodes and edges from another graph.
+   * Note this doesn't check for duplicates, nor does it connect the graphs.
+   */
+  extend(graph: Graph, prefix: string = "") {
+    let finalPrefix = prefix;
+    const nodeIds = Object.values(graph.nodes).map((node) => node.id);
+    if (nodeIds.every(isUuid)) {
+      finalPrefix = "";
+    }
+
+    const prefixed = (id: string) => {
+      return finalPrefix ? `${finalPrefix}:${id}` : id;
+    };
+
     Object.entries(graph.nodes).forEach(([key, value]) => {
-      this.nodes[key] = value;
+      this.nodes[prefixed(key)] = { ...value, id: prefixed(key) };
     });
 
+    const newEdges = graph.edges.map((edge) => {
+      return {
+        ...edge,
+        source: prefixed(edge.source),
+        target: prefixed(edge.target),
+      };
+    });
     // Add all edges from the other graph
-    this.edges = [...this.edges, ...graph.edges];
+    this.edges = [...this.edges, ...newEdges];
+    const first = graph.firstNode();
+    const last = graph.lastNode();
+    return [
+      first ? { id: prefixed(first.id), data: first.data } : undefined,
+      last ? { id: prefixed(last.id), data: last.data } : undefined,
+    ];
   }
 
   trimFirstNode(): void {