YantraJS

Yantra (Machine in Sanskrit) is a Managed JavaScript Engine for .NET (Core and Standard 2) written completely in C#.

Node and V8's tight C++ intgration makes it difficult to write plugins, resulting in unresolved bugs and very complicated source code structure.

C# offers platform independent near native performance, so YantraJS is designed to replace parts of Node that requires high performance.

Multi threaded shared object cache are difficult to achieve in Node, but YantraJS offers smooth connectivity between C# and JavaScript as both objects live under same runtime.

NuGet

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

Features

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. Decimal support, number with 0.2m prefix has a new literal type called decimal, typeof 0.2m is 'decimal'.
25. Easily marshal CLR Object to JavaScript and other way around
26. CSX Module support
27. Mixed module system, YantraJS supports require and import.
28. Explicit resource management with using and await using keywords.
29. AOT ready (Source Generators have been used for loading Runtime Objects).

* 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,

• Module names may or may not have extensions.
• File will be loaded if same name exists on disk.
• Engine will try to load ${name}.csx file, if it exists it will load the module.
• Engine will then try to load ${name}.js file, if it exits it will load the module.
• Otherwise it will travel to parent directory and search modules in node_modules folder in exact same order defined earlier.

Roadmap

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. Next in plan is Network API, Simple fetch is available in YantraContext, we will focus on adding Stream API.
2. Unified API to access system resources through JavaScript modules that dynamically utilize .NET objects.
3. Add node modules compatibility.
4. V8 Protocol Implementation is in progress.

Documentation

1. Introduction
   • Features
2. Expression Compiler
3. JavaScript Engine
   • CommonJS Module Support
   • CSX Module Support

Discussions

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