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by brabel 2213 days ago
Deno is great ! It makes it possible for us to write TypeScript and execute it really fast, without a build system to worry about!

The only thing that, to me, is a big problem, is that, even though you have types in your TS code, you're basically throwing them away at runtime, wasting huge opportunities for optimisation that even the V8 can't recover. If V8 had support for strictly typed TS code, can you imagine how fast it could get it to run?! I think that's the next stage in the evolution of JavaScript/Node/Deno: Node -> Deno -> Done.
1 comments
osrec 2213 days ago
I'm no expert on compilers/interpreters, but wouldn't the added overhead of type checking cause things to slow down (genuine question)?
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brabel 2212 days ago
No, because it does the type checking already: it just fails to keep the type data into the runtime, which could be highly optimized if it had types. V8 apparently "generates" types on-the-go to make JS run fast, so if it had pre-built types it could already run the faster version of the code from the start.
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osrec 2212 days ago
Ah, understood. So, almost like Java compiling a class to bytecode before running in the JVM?
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brabel 2212 days ago
Yes, something like that. Interestingly enough, Dart has a mode to compile to the AST, so that when you run it, the interpreter does not need to parse the text again and check the types, it just starts straight off an AST. The TS compiler and V8 could definitely do something similar.
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