Add WS as a dep of notebooks (#8154)

* add ws as an optional dep of noteoboks

* fix method of adding ws

* fix parsing for yarnrc

* remove optional reps

extensions/notebook/extension.webpack.config.js

@@ -8,13 +8,27 @@
 'use strict';
 
 const withDefaults = require('../shared.webpack.config');
+const fs = require('fs');
+const path = require('path');
+
+const externals = {
+	'node-fetch': 'commonjs node-fetch'
+};
+
+// conditionally add ws if we are going to be running in a node environment
+const yarnrcPath = path.join(__dirname, '.yarnrc');
+if (fs.existsSync(yarnrcPath)) {
+	const yarnrc = fs.readFileSync(yarnrcPath).toString();
+	const properties = yarnrc.split(/\r?\n/).map(r => r.split(' '));
+	if (properties.find(r => r[0] === 'runtime')[1] === '"node"') {
+		externals['ws'] = 'commonjs ws';
+	}
+}
 
 module.exports = withDefaults({
 	context: __dirname,
 	entry: {
 		extension: './src/extension.ts'
 	},
-	externals: {
-		'node-fetch': 'commonjs node-fetch'
-	}
+	externals: externals
 });