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Discussion on: JavaScript typed arrays: Unexpected overflow

antogarand profile image
Antony Garand Author

I consider this a quirk for two reasons:

  1. In C/C++, the answer would be 0 for both variables
  2. The following two snippets don't have the same value
const first = Uint8Array.of(255);
const second = Uint8Array.of(255);
const firstValue = ++first[0];
const secondValue = second[0];

This is counter-intuitive.

lexlohr profile image
Alex Lohr

Just because a language is specified different to C/C++ doesn't make it quirky. All of your example are just showing the specified behavior of any flavour of modern ECMAscript.

I would only consider this a quirk if the standard operators suddenly changed the specified behavior to handle typed arrays differently, i.e. if you assigned the result to another field of a Uint8Array and the results would differ or if assignments to untyped variables suddenly exposed the same overflow as the typed array ones.