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Comment by tsahyt | Hacker News Reader

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tsahyt·

It is. Sounds like a big waste of performance to me.

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You'd be surprised at how well JavaScript performs when allowed.

The scary part of JavaScript is not performance, it is the hell of inconsistency.

'1' - 0 is 1. Guess what '1' + 0 is? Nope, it's '10'.

Crockford's JavaScript truth table is mind-bending. On top of that, semicolon insertion.

Type coercion and asi are probably the least troublesome odd parts of js I encounter day to day.

I find the weird scoping rules around 'this' and the verbosity of anonymous functions far worse. [1]

(Sincerely and non-rhetorically) Do you really find the former more annoying than the latter? I see a lot of people using those examples to call out JS inappropriateness for development, but it seems like they're focusing on the wrong things to me.

[1] I know they can be fixed by using a language that compiles down to JS. So can the parent's criticisms.

Not inconsistency to me. + is a string concatenation operator, - is not (maybe it could be) and '1' - 0 is just a fallback.

Not really scary day-to-day. If you want to do integer math, make sure you're dealing with integers.

It performs well, until the code is too complex for the JIT compiler to get type inference / speculative optimizations right. Then it suddenly performs very, very poor, because it falls back on dynamic (very slow compared to inline) dispatch and doubles instead of ints.

The language seems in need of refinement to get significant performance in match of JVM JIT, not to mention c.

Probably. I haven't witnessed that yet though.

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