Put worker behind setting

extensions/ipynb/package.json

@@ -39,6 +39,12 @@
             "scope": "resource",
             "markdownDescription": "%ipynb.pasteImagesAsAttachments.enabled%",
             "default": true
+          },
+          "ipynb.experimental.serialization": {
+            "type": "boolean",
+            "scope": "resource",
+            "markdownDescription": "%ipynb.experimental.serialization%",
+            "default": false
           }
         }
       }

extensions/ipynb/package.nls.json

@@ -2,6 +2,7 @@
 	"displayName": ".ipynb Support",
 	"description": "Provides basic support for opening and reading Jupyter's .ipynb notebook files",
 	"ipynb.pasteImagesAsAttachments.enabled": "Enable/disable pasting of images into Markdown cells in ipynb notebook files. Pasted images are inserted as attachments to the cell.",
+	"ipynb.experimental.serialization": "Experimental feature to serialize the Jupyter notebook in a worker thread.",
 	"newUntitledIpynb.title": "New Jupyter Notebook",
 	"newUntitledIpynb.shortTitle": "Jupyter Notebook",
 	"openIpynbInNotebookEditor.title": "Open IPYNB File In Notebook Editor",

extensions/ipynb/src/notebookSerializer.ts

@@ -107,10 +107,15 @@ export class NotebookSerializer implements vscode.NotebookSerializer {
 			data.metadata.indentAmount :
 			' ';
 
-		return this.serializeViaWorker({
-			notebookContent: sorted,
-			indentAmount
-		});
+		const experimentalSave = vscode.workspace.getConfiguration('ipynb').get('experimental.serialization', false);
+		if (experimentalSave) {
+			return this.serializeViaWorker({
+				notebookContent: sorted,
+				indentAmount
+			});
+		} else {
+			return Promise.resolve(JSON.stringify(sorted, undefined, indentAmount));
+		}
 	}
 }