Great point! I would add that "clever code" is often is just saving symbols, while sacrificing readability, expressiveness and distorting meaning.
In the example with "&&" we rely on the fact that in JS code on the right part of logical AND won't be executed. So it is sort of a "hack". And I think that majority of such "clever code" examples are in fact hacks.
It's important to understand that when we write code - we have different sorts of stakeholders. And one of important categories of those are developers themselves!
It is important that code not only performs some useful action, but is also convenient to work with and is understandable.
Maksim nailed it.
Regarding JSX though, it's a totally valid use case for using && and ternary operators since you're conditionally rendering pieces of UI this way. From a declarative perspective, it's fairly clean.
Love the Number(id) example too. Not only does it handle null values, but you can more clearly understand that you're converting to a number.
I disagree that 5e3 is clever. Exponential notation is something that every coder should learn. It appears in a lot of places and is much clearer that expanded numbers.
I did a lot of work with nanoseconds much, and I would have to see 1500000000 in the code versus 1.5e9. With larger numbers the exponential format is preferred.
Of course, I'd also like a language that allows separators (I did in Leaf, like 5_000.
Note though, on the second I think any api that accepts something other than seconds for duration by default is broken. Seconds is the natural time, milliseconds is unusual. Thus a conversion function would be nice to see there.
It's clever in that scenario because seeing the exponential notation for most people will require more brain processing power than simply seeing 5000 milliseconds or 5 seconds.
It also really just depends on what you're building. Web development rarely requires you to use exponential notation, and so declaring it as "something that every coder should learn" is not an absolute that I can get behind.
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