How can I debug compilation?

[urbanhop]

This is less an issue but a request for advice. I try to change the way code for namespaces is emitted.

Currently the typescript code

namespace A{
    var x = 42;
}

is emitted as

var A;
(function (A) {
    var x = 42;
})(A || (A = {}));

which I want to change to be emitted as

    var A_x = 42;

Obviously, all references to x also need to become A_x .

I walkted through emitter.ts and declarationEmitter.ts but without being able to stepping through the compilation with a debugger it is hard to fully understand the pieces. So my question:

How can I debug compilation ?
Hints on my namespace hack are also appreciated.

[DanielRosenwasser]

If you're on Windows with a program that can use the script debugging interface (e.g. Visual Studio), you can use cscript with with /X flag to signal that it should stop on the first statement.

If you want to make it faster, use the Chakra engine using something like the flag /E:{16d51579-a30b-4c8b-a276-0ff4dc41e755}.

If you don't have that privilege, you can use node-inspector and run the compiler with node --debug-brk build/local/tsc.js.

As a word of caution, if you're intending on sending this out as a PR, I don't think we're inclined to accept something like that (or at least, we'd need a proposal to consider first). If it's for your own personal purposes, I fully encourage you to learn about the compiler and experiment. I'd look into emitIdentifier in emitter.ts.

[urbanhop]

Thank you so much Daniel, this was very helpful.

No PR indended, pure private hack for some very specific reasons.