Add version property to JavaScript documents

Author: davidbrochart

javascript/src/api.ts

@@ -82,6 +82,11 @@ export interface ISharedBase extends IObservableDisposable {
  * This is used by, for example, docregistry to share the file-path of the edited content.
  */
 export interface ISharedDocument extends ISharedBase {
+  /**
+   * Document version
+   */
+  readonly version: string;
+
   /**
    * Document state
    */

javascript/src/ycell.ts

@@ -185,6 +185,11 @@ export class YBaseCell<Metadata extends nbformat.IBaseCellMetadata>
     this.ymodel.observeDeep(this._modelObserver);
   }
 
+  /**
+   * Document version
+   */
+  readonly version: string = '0.1.0';
+
   /**
    * Cell notebook awareness or null if the cell is standalone.
    */

javascript/src/yfile.ts

@@ -27,6 +27,11 @@ export class YFile
     this.ysource.observe(this._modelObserver);
   }
 
+  /**
+   * Document version
+   */
+  readonly version: string = '0.1.0';
+
   /**
    * Creates a standalone YFile
    */

javascript/src/ynotebook.ts

@@ -66,6 +66,11 @@ export class YNotebook
     this.ymeta.observeDeep(this._onMetaChanged);
   }
 
+  /**
+   * Document version
+   */
+  readonly version: string = '0.1.0';
+
   /**
    * Creates a standalone YNotebook
    *