Writing code for both computers and humans
tonymottaz.com
Writing code for both computers and humans
1–10 of 32 posts
Re: Writing code for both computers and humans
#2I agree with the author that this is a reasonable way to indicate their intent. But I've seen so many accidentally ineffectual code snippets that if I saw this code I'd be inclined to delete it unless there was also a comment expressing its purpose.
Re: Writing code for both computers and humans
#3I don't think what the author says is the intent of the code. isNaN() returns true not just for NaN but for anything that is "not a number"[1]. For example, it returns true for things like "hello".
So it just canonicalizes everything that is not a number into NaN.
[1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
Re: Writing code for both computers and humans
#4I agree with the author that this is a reasonable way to indicate their intent. But I've seen so many accidentally ineffectual code snippets that if I saw this code I'd be inclined to delete it unless there was also a comment expressing its purpose.
And a comment on its own would be enough anyway
Re: Writing code for both computers and humans
#5I don't think what the author says is the intent of the code. isNaN() returns true not just for NaN but for anything that is "not a number"[1]. For example, it returns true for things like "hello". So it just canonicalizes everything that is not a number into NaN. [1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
There's a whole set of different floating-point values which are NaN, and this canonicalizes them into one particular NaN, as I understand it.
I'm not even sure that covering type conversions was intended here.
Re: Writing code for both computers and humans
#6I agree with the author that this is a reasonable way to indicate their intent. But I've seen so many accidentally ineffectual code snippets that if I saw this code I'd be inclined to delete it unless there was also a comment expressing its purpose.
And a comment on its own would be enough anyway
Yeah, ideally you’d have some kind of static typing to restrict the code to only use Number, and then a comment that says what the function does in case of NaN.
Re: Writing code for both computers and humans
#7I don't think what the author says is the intent of the code. isNaN() returns true not just for NaN but for anything that is "not a number"[1]. For example, it returns true for things like "hello". So it just canonicalizes everything that is not a number into NaN. [1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
This is my issue with js; isNaN looks related to NaN in a 1-1 mapping as in, testing ‘x is NaN’ but it doesn’t. So the naming is confusing as it does more than that, isNotNumeric() or so.
Re: Writing code for both computers and humans
#8I don't think what the author says is the intent of the code. isNaN() returns true not just for NaN but for anything that is "not a number"[1]. For example, it returns true for things like "hello". So it just canonicalizes everything that is not a number into NaN. [1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
Funny. If this is effectively so, the code is actually fairly ok and clearly expresses the intent for humans yet the OP claiming exactly that managed to still misunderstand the code because they made up a precondition ('defaultValue is going to be a number') probably exactly because they refused to 'To answer this question, you need to start looking around for clues' so they missed the clue [1]; or maybe rather the clue is: dynamically typed so expecting a number is a wrong assumption. Still I'd argue a comment explaining why it's in this particular case fine that any non-sane input translates to NaN and not an error might be worth it Well, unless that is clear from the surrounding code :)
Re: Writing code for both computers and humans
#9I don't think what the author says is the intent of the code. isNaN() returns true not just for NaN but for anything that is "not a number"[1]. For example, it returns true for things like "hello". So it just canonicalizes everything that is not a number into NaN. [1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
Thanks, your explanation makes a lot more sense. A short comment would be useful in the original code.
Written as is, the original code looks surprising. I've seen this kind of easily simplifiable multiple times in large codebases, after years of refactoring and automated transformations.
Re: Writing code for both computers and humans
#10I don't know if that was the real intent of this code, considering all the weird nuance around NaN in Javascript - however I agree with the point the author makes, and will take it one step further:
We should be building these semantics directly into our languages, not relying on programmers to strictly follow a "best practice". In this case, it would be making values non-nullable and baking in Result/Option/etc style types that force programmers into handling the null (or NaN) case.