NetJs: A .NET to TypeScript and JavaScript compiler

by yulaow • 12 years ago

67 30 12 years ago

dangoor2• 12 years ago

I find that the TypeScript compiler is annoyingly slow and I cringe imagining a workflow that involves another compiler in front of the TypeScript compiler. Granted, you'd probably do most of your tests and such at the C# level and only step into JS as the final step... but iterating through those last steps would be annoying.

Especially when you consider a "just hit reload" development cycle as the competition.

peterchon• 12 years ago

I couldn't agree more.

sherbet• 12 years ago

Our TypeScript project is ~20K SLOC. It compiles in roughly (I haven't measured exactly) the same amount of time it takes to compile 100 SLOC.

Since the Typescript compiler itself is > 2MB of minified js, it doesn't surprise me that compiling any TS has at least a second overhead.

What's more important to me is that:

- The compiler performance scales as the codebase increases in size.

- Incremental builds are fast. (ie the -watch option).

So far I have found both to be true. Incremental builds take < .5 sec on my laptop. That means I get a cute red-squiggly in Visual Studio in a convenient amount of time. Ultimately, that's half the reason for using TS in the first place; if it didn't improve our productivity, we wouldn't be using it.

dangoor2• 12 years ago

Thanks for that bit of data. That makes good sense, and I should give it another try.

jordibunster• 12 years ago

-watch doesn't find new files yet, does it?

Keats• 12 years ago

Are you using a grunt/gulp task to do the incremental build or doing it via VS/tsc directly ?

Touche• 12 years ago

I don't think the point here is to write your entire app in C#. TypeScript is already close enough.

I think the point is that you have some existing libraries that would be useful in a web application, you could go ahead and compile those down to TS and use them within your TS code.

duncanawoods• 12 years ago

I wrote myself a similar tool for myself using NRefactory so I can fill you in:

I found that converting 10k of C# was incredibly quick and the overall build time was still totally dominated by the slow TypeScript compiler.

You are right that the development time is spent unit-testing C# and very rarely invoking the TS compiler so rather than making the workflow worse, it improves it immeasurably. The alternative to recompile TS each time and use Karma and Chrome dev tools is unbearably slow and clunky in comparison.

The real win I was after was that the quality of the test tools and debugger for .Net. Using a tool like TestDriven.Net from visual studio so from a r-click I have test coverage, performance, edit-and-continue and all the benefits of the Visual Studio debugger.

The generation to typescript is more of a publish step than part of the development cycle. I also convert the NUnit tests to Jasmine so I run the same test suite across the generated javascript. This does catch issues because there are differences, like lexical scoping, that my cs2ts tool did not try to solve.

Revex• 12 years ago

Seems pretty neat. Sort of like a GWT for .Net. Except with the added benefit of being able to go into an intermediary form of TypeScript.

I see something like this really being beneficial when building a Single Page Application, or porting a Desktop Application to a SPA.

camus22• 12 years ago

I get you can port some code,but you're not going to port your xaml code to javascript with this.How do you write dom manipulation in C# then compile it directly to usable javascript?

samirahmed• 12 years ago

at first glance, i thought the mere edge cases alone (listed under limitations in the readme) would be sufficient reason to stay well away from this c# -> js route.

however on second glance ... there have been numerous times where I have written c# server side with 'UI Model' Classes that use to serialize to XML/json for consumption by the client/browser and corresponding models in javascript/typescript. The C# -> Typescript conversion would save me a lot of time (and automate keeping the two in sync) and I would imagine for that niche case it would be totally worth it.

cmdkeen• 12 years ago

I've used Typelite and T4TS to generate Typescript definition files (interfaces effectively) for my C# code. I'm not sure about going further than that and exposing logic.

soundoflight• 12 years ago

This is really cool. I would love to see this mature a bit more.

edtechdev• 12 years ago

Looks nice, I added it to this list of languages that compile to JavaScript (in the "C#, F#, .NET related languages" section): https://github.com/jashkenas/coffee-script/wiki/List-of-lang...

camus22• 12 years ago

why did not MS write a pure C# typescript compiler?

the js one is so slow it's barely usable. It should be priority 1! write something in C# or even C++,that should'nt be that hard,or is it?

WorldWideWayne• 12 years ago

I'm thinking that they probably didn't want to scare away web devs that don't like .NET.

I believe that their compiler also runs under Node.JS, which is easily a much lighter cross-platform solution than requiring Mono (which would be needed for a C# compiler).

_random_2• 12 years ago

Marketing and politics.

AsmMAn3• 12 years ago

It may change now Microsoft and Mono are working in .NET platform together.

MichaelGG4• 12 years ago

TypeScript's written in TS/JS? Yikes. Certainly better off writing it in a better language and then crosscompiling to JS for the people that want to do "npm install typescript".

neil_s• 12 years ago

The day I can write C# on both the server and client, instead of js with Node.js, I'll be soooo happy.

_random_2• 12 years ago

Oh man, that would hit right the spot!

AsmMAn3• 12 years ago

Is not exactly this the universal(or something so) .NET platform new promise?

janekk• 12 years ago

I don't think so. It failed with Silverlight, and was nasty with ASP.NET webforms. Microsoft now champions ASP.NET MVC on the server and TypeScript on the client. They also use TypeScript to write huge JavaScript apps for consumers.

MichaelGG4• 12 years ago

You can use WebSharper and get it with F#. It even has commercial backing. Comes with a neat little RPC system so you can effortlessly decide which code runs where.

There were also other projects that allowed this with C#, I just forget their names.

visualR• 12 years ago

Excellent. How did you know I wanted this? =)

onatm• 12 years ago

why don't you just compile to js?

http://i.imgur.com/0DgQh4e.jpg

AsmMAn3• 12 years ago

It seems great! thanks! By .NET in this context, do you mean you translate from CIL to TypeScript? does it mean it works with any .NET language? also, it's amazing it's written in C#.

rdo• 12 years ago

Here's what Anders thinks about C# to js cross compilation at about 2m 20s into this interview at Build.

http://channel9.msdn.com/Events/Build/2014/9-010

"That is darn near impossible to do with any level of fidelity that is meaningful"

"If you're going to write for the web, write for the web."

MichaelGG4• 12 years ago

Perhaps he's biased because he made TypeScript? Then again, this is from the main guy behind C#. The language that chose "delegate" as it's lambda keyword (fixed it later at least), decided tuples aren't worth supporting, went with C-style optional parameters after years of promoting overloads instead (both terrible ideas), and barely has type inference. (Just a few things that popped in the top of my mind.)

Write for the web seems like a lame excuse to not embrace better languages and deal with the issues in cross compilation.

MichaelGG4• 12 years ago

This might be a perfect backdoor in getting .NET into some frontend projects. Depending on the dev and PM, I find there can be significant pushback on going all-out using WebSharper or anything that isn't JS or close to it.

This way, the JS output can be considered source, checked in, diffs might make sense, and the real source could be hidden in a tarball until it's too late.

NetJs: A .NET to TypeScript and JavaScript compiler

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