Visual Studio “15” Introduces New JavaScript Language Service, Salsa

Microsoft Visual Studio team just announced a new JavaScript language service, codenamed “Salsa,” that can be installed for Visual Studio “15” preview. The news was announced via a blog post by Microsoft’s Bowden Kelly, Program Manager, VS Client.

From the blog:

Language services are responsible for providing syntax highlighting, completion lists, signature help, and other tooling features for a specific language inside the IDE. Salsa delivers many improvements over the existing JavaScript language service such as improved module support, full ES6/ES7 syntax coverage, and JSX support.

By default, the new feature “Salsa” is not enabled in Visual Studio “15” Preview. To enable Salsa in Visual Studio “15” Preview, you will have to change the value of a key named “TypeScriptLanguageService“ in Windows registry. Save the following snippet as a local file named salsa.reg, run it to update the registry, and then restart Visual Studio.

  1. Windows Registry Editor Version 5.00  
  3. [HKEY_CURRENT_USER\SOFTWARE\Microsoft\VisualStudio\15.0\TypeScriptLanguageService]  
  5. "UseTypeScriptExperimental"=dword:00000001 

To disable this feature, change value of the “TypeScriptLanguageService” to 00000000 instead of 00000001.

Some of the key features of Salsa:

  • Intellisense based of type interface
  • Intellisense based on JsDoc annotations
  • Intellisense based on TypeScript definitions
  • Automatic acquisition of type definitions
  • Compiling JavaScript down-level
  • Mixing JavaScript and TypeScript languages
  • JSX and React support

Learn more about these features, some known issues, and how to use Salsa in Visual Studio “15” preview.