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Comment by evmar | Hacker News Reader

The TypeScript compiler is the canonical corpus of code written by TypeScript experts, and I learned a lot of interesting style from the time I've spent with it. (Fun fact: they don't use 'class' in the compiler at all, but instead have a different pattern for passing around interfaces+state that is much more TypeScript-y.)

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Could you cite an example of the interfaces+state pattern? You've piqued my interest.

Seconded, I'm also very interested.

It looks like there is a lot of legacy code hanging out in the compiler [1], i.e. prefer module over namespaces.

[1] - https://github.com/Microsoft/TypeScript/blob/master/src/comp...

It's also strange to me why they inline their interfaces, rather than organizing them in a common folder / module.

Fun fact: they don't use 'class' in the compiler at all

Looks like a class to me: https://github.com/Microsoft/TypeScript/blob/master/src/comp...

What strikes me first is the comment above the function :

// Keep the class inside a function so it doesn't get compiled if it's not used.

I didn't know it was possible.

We do use classes in the test harness, services layer, and to polyfill es6 Map. We just don't use them in the design of any compiler subsystems.

This is very interesting to me.

Is the reasoning behind this documented anywhere?

I could only find instructions the coding guideline indicating as much (here: https://github.com/Microsoft/TypeScript/wiki/Coding-guidelin...) but couldn't find why. I'd love to know why, may better inform my usage of typescript.

For better or worse? I've avoided classes in our codebase because I don't like the lack of privates via closure (revealing module pattern) and it's transpiler overhead, but it's a very powerful organization tool. I've found code to be much neater in the class format.

Looks like C++ circa 2008. Careful with those abstractions. That seems a stone's throw away from template metaprogramming.

does anyone have some recommendation on how to debug typescript compiler, it seems like console does not work there, I am trying to just step through tsc.ts, but gulp local always complains that console is not defined. Is there any alternative in stepping through the compiler?

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