mol-state: StateBuilder.To.insert

src/mol-state/state/builder.ts

@@ -69,6 +69,27 @@ namespace StateBuilder {
             return new To(this.state, t.ref, this.root);
         }
 
+        /**
+         * Inserts a new transform that does not change the object type and move the original children to it.
+         */
+        insert<T extends StateTransformer<A, A, any>>(tr: T, params?: StateTransformer.Params<T>, options?: Partial<StateTransform.Options>, initialCellState?: Partial<StateObjectCell.State>): To<StateTransformer.To<T>> {
+            // cache the children
+            const children = this.state.tree.children.get(this.ref).toArray();
+
+            // add the new node
+            const t = tr.apply(this.ref, params, options);
+            this.state.tree.add(t, initialCellState);
+
+            // move the original children to the new node
+            for (const c of children) {
+                this.state.tree.changeParent(c, t.ref);
+            }
+
+            this.editInfo.count++;
+            this.editInfo.lastUpdate = t.ref;
+            return new To(this.state, t.ref, this.root);
+        }
+
         update<T extends StateTransformer<any, A, any>>(transformer: T, params: (old: StateTransformer.Params<T>) => StateTransformer.Params<T>): Root
         update(params: any): Root
         update<T extends StateTransformer<any, A, any>>(paramsOrTransformer: T, provider?: (old: StateTransformer.Params<T>) => StateTransformer.Params<T>) {

src/mol-state/transform.ts

@@ -48,10 +48,14 @@ namespace Transform {
         }
     }
 
-    export function withParams<T>(t: Transform, params: any): Transform {
+    export function withParams(t: Transform, params: any): Transform {
         return { ...t, params, version: UUID.create22() };
     }
 
+    export function withParent(t: Transform, parent: Ref): Transform {
+        return { ...t, parent, version: UUID.create22() };
+    }
+
     export function createRoot(props?: Props): Transform {
         return create(RootRef, StateTransformer.ROOT, {}, { ref: RootRef, props });
     }

src/mol-state/tree/transient.ts

@@ -90,6 +90,14 @@ class TransientTree implements StateTree {
         this.childMutations.set(parent, set);
     }
 
+    changeParent(ref: StateTransform.Ref, newParent: StateTransform.Ref) {
+        ensurePresent(this.transforms, ref);
+
+        const old = this.transforms.get(ref);
+        this.removeChild(old.parent, ref);
+        this.addChild(newParent, ref);
+    }
+
     add(transform: StateTransform, initialState?: Partial<StateObjectCell.State>) {
         const ref = transform.ref;