Add unique ID to each node in the state tree

modern/src/Actions.ts

@@ -2,6 +2,7 @@ import { MakiTree, ModernAction, ModernStore, XmlTree } from "./types";
 import JSZip from "jszip";
 import * as Utils from "./utils";
 import initialize from "./initialize";
+import initializeStateTree from "./initializeStateTree";
 import { run } from "./maki-interpreter/virtualMachine";
 import System from "./runtime/System";
 import runtime from "./runtime";
@@ -10,8 +11,13 @@ export function setMakiTree(makiTree: MakiTree): ModernAction {
   return { type: "SET_MAKI_TREE", makiTree };
 }
 
-export function setXmlTree(xmlTree: XmlTree): ModernAction {
-  return { type: "SET_XML_TREE", xmlTree };
+export function setXmlTree(xmlTree: XmlTree) {
+  return async dispatch => {
+    dispatch({
+      type: "SET_XML_TREE",
+      xmlTree: await initializeStateTree(xmlTree),
+    });
+  };
 }
 
 export function gotSkinUrl(skinUrl: string, store: ModernStore) {

modern/src/initializeStateTree.ts

@@ -0,0 +1,15 @@
+import { XmlTree } from "./types";
+import * as Utils from "./utils";
+
+function mapTree(node, cb) {
+  const children = node.children || [];
+  return cb({ ...node, children: children.map(child => mapTree(child, cb)) });
+}
+
+export default async function initializeStateTree(
+  xmlTree: XmlTree
+): Promise<XmlTree> {
+  return mapTree(xmlTree, node => {
+    return { ...node, uid: Utils.getId() };
+  });
+}

modern/src/utils.js

@@ -1,5 +1,10 @@
 import { xml2js } from "xml-js";
 
+let i = 0;
+export function getId() {
+  return i++;
+}
+
 export function isPromise(obj) {
   return obj && typeof obj.then === "function";
 }