Should we eventually add support for parsing TypeScript? (3 of 3)
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A major milestone: Hermes can now parse the entirety of Facebook's JavaScript codebase, both for web and RN, including all ES6+ features, JSX and Flow type annotations, no Babel or any preprocessing. A single server VM with 24 workers parses 450MB/s. (1 of 3)
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We can literally parse 4GB of JavaScript in 10 seconds on a single server VM.
Note that this is just parsing, not compilation. The compiler doesn't support all features yet, but we are getting there. (2 of 3)
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For the record, I am not surprised by the replies to this tweet :-)
Sincere question: why would it be useful in practice if Hermes could parse TypeScript?
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@tmikov
Please focus on full ES2016+ support first, so we reduce the amount of Babel we need to have. It's 2020 and we still have to transform `const` to `var` in React Native.
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@tmikov
Absolutely; outside of Facebook, TypeScript is king for bringing strong typing to React projects.
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@tmikov
I suspect you already know the answer: yes! I haven’t seen a single team use TypeScript and go back to vanilla JS.
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@tmikov
YESSSSS. Does Facebook has zero typescript? That's weird. I didn't know Flow was so used there.
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@tmikov
I actually like that TypeScript syntax only exists at compile time (and not at runtime).
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