[goldenkey]

I agree, however that's all fine and well but it turns the languages syntax into dogshit. A babel plugin (transpiling) would be ideal.

On the same note, the original intent was for NaN to be insidious and propagate into every derived calculation or comparison, thus making it easy to tell if a mathematical function had failed, without having to add conditionals at every step within it. Which makes a lot of sense. However, not being able to know exactly where the NaN was produced is kind of shit. Now, if NaN had a stack trace property like Error (exception) objects...it would make this behavior much more useful. Makes me wonder if the prototype of NaN can be extended, hm.

[afiori]

NaNs cannot be extended in any way, in many interpreters NaN is used to "hide" pointers in 64 bit floats using the 52 free bits in NaN values.

IMO NaN should have never existed, like signed zeros, (I am more agnostic about [signed] Infinity) I think that they were implemented in IEEE 754 because the encoding had space left for them.

I not an expert in any way on this this is literally a personal opinion.

[goldenkey]

Right. I was thinking that maybe NaN in JS was more than just the IEEE version we see in languages closer to the metal.