feat(store): add parent relation in page element

src/store/page/index.ts

@@ -43,6 +43,6 @@ export class Page {
 		const pageModel: any = JSON.parse(FileUtils.readFileSync(pagePath, 'utf8'));
 
 		this.name = pageModel.name;
-		this.root = new PageElement(pageModel.root, this.store);
+		this.root = new PageElement(this.store, pageModel.root);
 	}
 }

src/store/page/page_element.ts

@@ -6,18 +6,21 @@ import { Store } from '..';
 
 export class PageElement {
 	@MobX.observable private children: PageElement[] = [];
+	private parent: PageElement | undefined;
 	private patternPath: string;
 	private pattern?: Pattern;
 	@MobX.observable private propertyValues: Map<string, PropertyValue> = new Map();
 
 	// tslint:disable-next-line:no-any
-	public constructor(json: any, store: Store) {
+	public constructor(store: Store, json: any, parent?: PageElement) {
+		this.parent = parent;
+
 		this.patternPath = json['pattern'];
 		const pattern: Pattern | undefined = store.getPattern(this.patternPath);
 		if (pattern) {
 			this.pattern = pattern;
 		} else {
-			console.warn(`Ignoring unknown pattern ${this.patternPath}`);
+			console.warn(`Ignoring unknown pattern "${this.patternPath}"`);
 			return;
 		}
 
@@ -40,7 +43,7 @@ export class PageElement {
 	// tslint:disable-next-line:no-any
 	protected createElementOrValue(json: any, store: Store): PageElement | PropertyValue {
 		if (json && json['_type'] === 'pattern') {
-			return new PageElement(json, store);
+			return new PageElement(store, json, this);
 		} else {
 			return json;
 		}
@@ -50,6 +53,10 @@ export class PageElement {
 		return this.children;
 	}
 
+	public getParent(): PageElement | undefined {
+		return this.parent;
+	}
+
 	public getPattern(): Pattern | undefined {
 		return this.pattern;
 	}
@@ -64,6 +71,10 @@ export class PageElement {
 		return value;
 	}
 
+	public isRoot(): boolean {
+		return this.parent === undefined;
+	}
+
 	// tslint:disable-next-line:no-any
 	public setPropertyValue(id: string, value: any): void {
 		if (!this.pattern) {