feat(ui): add addEdgeToMetadata graph helper

invokeai/frontend/web/src/features/nodes/util/graph/generation/Graph.test.ts

@@ -522,6 +522,21 @@ describe('Graph', () => {
       });
     });
 
+    describe('addEdgeToMetadata', () => {
+      it('should add an edge to the metadata node', () => {
+        const g = new Graph();
+        const n1 = g.addNode({
+          id: 'n1',
+          type: 'img_resize',
+        });
+        g.upsertMetadata({ test: 'test' });
+        g.addEdgeToMetadata(n1, 'width', 'width');
+        const metadata = g._getMetadataNode();
+        expect(g.getEdgesFrom(n1).length).toBe(1);
+        expect(g.getEdgesTo(metadata as unknown as AnyInvocation).length).toBe(1);
+      });
+    });
+
     describe('setMetadataReceivingNode', () => {
       it('should set the metadata receiving node', () => {
         const g = new Graph();

invokeai/frontend/web/src/features/nodes/util/graph/generation/Graph.ts

@@ -372,6 +372,21 @@ export class Graph {
     return metadataNode;
   }
 
+  /**
+   * Adds an edge from a node to a metadata field. Use this when the metadata value is dynamic depending on a node.
+   * @param fromNode The node to add an edge from
+   * @param fromField The field of the node to add an edge from
+   * @param metadataField The metadata field to add an edge to (will overwrite hard-coded metadata)
+   * @returns
+   */
+  addEdgeToMetadata<TFrom extends AnyInvocation>(
+    fromNode: TFrom,
+    fromField: OutputFields<TFrom>,
+    metadataField: string
+  ): Edge {
+    // @ts-expect-error `Graph` excludes `core_metadata` nodes due to its excessively wide typing
+    return this.addEdge(fromNode, fromField, this._getMetadataNode(), metadataField);
+  }
   /**
    * Set the node that should receive metadata. All other edges from the metadata node are deleted.
    * @param node The node to set as the receiving node