added xmlKeys to xmlcomponent

ts/docx/document/body/columns.ts

@@ -1,7 +1,11 @@
 import {XmlComponent, Attributes} from "../../xml-components";
 
-export class Columns {
+export class Columns implements XmlComponent {
     private cols: Array<XmlComponent>;
+    
+    xmlKeys = {
+        cols: 'w:cols'
+    }
 
     constructor() {
         this.cols = new Array<XmlComponent>();

ts/docx/document/body/doc-grid.ts

@@ -1,7 +1,11 @@
 import {XmlComponent, Attributes} from "../../xml-components";
 
-export class DocumentGrid {
+export class DocumentGrid implements XmlComponent {
     private docGrid: Array<XmlComponent>;
+    
+    xmlKeys = {
+        docGrid: 'w:docGrid'
+    }
 
     constructor() {
         this.docGrid = new Array<XmlComponent>();

ts/docx/document/body/index.ts

@@ -5,9 +5,13 @@ import {PageMargin} from "./page-margin";
 import {Columns} from "./columns";
 import {DocumentGrid} from "./doc-grid";
 
-export class Body {
+export class Body implements XmlComponent {
     private body: Array<XmlComponent>;
-    
+
+    xmlKeys = {
+        body: 'w:body'
+    }
+
     constructor() {
         this.body = new Array<XmlComponent>();
         this.body.push(new SectionProperties());
@@ -16,7 +20,7 @@ export class Body {
         this.body.push(new Columns());
         this.body.push(new DocumentGrid());
     }
-    
+
     push(component: XmlComponent) {
         this.body.push(component);
     }

ts/docx/document/body/page-margin.ts

@@ -1,7 +1,11 @@
 import {XmlComponent, Attributes} from "../../xml-components";
 
-export class PageMargin {
+export class PageMargin implements XmlComponent {
     private pgMar: Array<XmlComponent>;
+    
+    xmlKeys = {
+        pgMar: 'w:pgMar'
+    }
 
     constructor() {
         this.pgMar = new Array<XmlComponent>();

ts/docx/document/body/page-size.ts

@@ -1,7 +1,11 @@
 import {XmlComponent, Attributes} from "../../xml-components";
 
-export class PageSize {
+export class PageSize implements XmlComponent {
     private pgSz: Array<XmlComponent>;
+    
+    xmlKeys = {
+        pgSz: 'w:pgSz'
+    }
 
     constructor() {
         this.pgSz = new Array<XmlComponent>();

ts/docx/document/body/section-properties.ts

@@ -1,8 +1,12 @@
 import {XmlComponent, Attributes} from "../../xml-components";
 
-export class SectionProperties {
+export class SectionProperties implements XmlComponent {
     private sectPr: Array<XmlComponent>;
     
+    xmlKeys = {
+        sectPr: 'sectPr'
+    }
+    
     constructor() {
         this.sectPr = new Array<XmlComponent>();
         this.sectPr.push(new Attributes({