YantraJS (Machine in Sanskrit)

Please visit GitHub repo at YantraJS


Yantra (Machine in Sanskrit) is a Managed JavaScript Engine for .NET Standard written completely in C#.


Name Package
YantraJS (With CSX Module Support) NuGet
YantraJS.Core (Compiler) NuGet
YantraJS.ExpressionCompiler (IL Compiler) NuGet
Yantra JS.ModuleExtensions (Fluent interface for module registration) Nuget


  1. Compiles JavaScript to .Net Assembly
  2. Strict Mode Only JavaScript*
  3. Arrow functions
  4. Classes
  5. Class members
  6. Enhanced object literals
  7. Template strings and tagged templates
  8. Destructuring
  9. let const
  10. Map, Set, WeakMap, WeakSet
  11. Symbols
  12. Subclassable built-ins
  13. Binary and Octal literals
  14. Module support
  15. Null coalesce
  16. Optional property chain identifier?.[], identifier?.(, identifier?.identifier
  17. Rest, Default and Spread Parameters
  18. Generators, iterators, for..of
  19. Async/Await
  20. Optional parameters
  21. Tail call optimization
  22. Many ES5 + ES6 features
  23. CommonJS & ES6 Module Support
  24. Easily marshal CLR Object to JavaScript and other way around
  25. CSX Module support
  26. Mixed module system, YantraJS supports require and import.
  27. Explicit resource management with using and await using keywords.

* Most JavaScript today is available in strict mode, we do not feel any need to support non strict mode as modules are strict by default.

Mixed modules

Currently YantraJS supports Both CommonJS and ES modules without any extra work, with little trick, module resolution is node like. Module loader loads module asynchronously, so import will work without any extra effort. However, require will run AsyncPump to wait till the module is loaded correctly. Unless you do some multithreading, mixed modules will not lead to any deadlocks.

Module loading order,


As we often have difficulty in writing cross environment scripts (browser and process such as node), we want to first implement basic common features on both.

  1. Generate Runtime with Source Generator, this will allow us to load Yantra in AOT environment. Currently Runtime objects are loaded through reflection, however we are moving reflection code to Source Generator one class a at a time.
  2. Next in plan is Network API, Simple fetch is available in YantraContext, we will focus on adding Stream API.
  3. Next is File API, we will implement FileSytem of Web Browser API and allow an easy native interface. So you can write script that will execute correctly in browser and in native
  4. V8 Protocol Implementation is in progress.


  1. Introduction
  2. Expression Compiler
  3. JavaScript Engine


We recommend using Github Discussion on this repository for any question regarding this product.

Special Thanks

  1. We are thankful to authors of Jurassic (we have incorporated number parser, promise and some unit tests from Jurassic.) https://github.com/paulbartrum/jurassic
  2. We are thankful to authors of EsprimaDotNet, we initially built prototype over EsprimaDotNet, but we chose to build our parser/scanner from scratch to support token spans. https://github.com/sebastienros/esprima-dotnet
  3. We are thankful to author of ILPack (we have incorporated saving IL to Assembly from this library.) https://github.com/Lokad/ILPack

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