Apply to instance: add error message when the endpoint is incorrect

Author: mtseluiko

forward_engineering/applyToInstanceHelper.js

@@ -5,8 +5,11 @@ const gremlin = require('../reverse_engineering/node_modules/gremlin');
 const applyToInstanceHelper = _ => ({
 	setUpDocumentClient(connectionInfo) {
 		const dbNameRegExp = /wss:\/\/(\S*).gremlin\.cosmos\./i;
-		const dbName = dbNameRegExp.exec(connectionInfo.gremlinEndpoint)[1];
-		const endpoint = `https://${dbName}.documents.azure.com:443/`;
+		const dbName = dbNameRegExp.exec(connectionInfo.gremlinEndpoint);
+		if(!dbName || !dbName[1]) {
+			throw new Error('Incorrect endpoint provided. Expected format: wss://<account name>.gremlin.cosmos.');
+		}
+		const endpoint = `https://${dbName[1]}.documents.azure.com:443/`;
 		const key = connectionInfo.accountKey;
 
 		return new CosmosClient({ endpoint, key });