Part of the "fun" of JavaScript is dealing with code which comes from before sensible features existed. For example, if you wanted to clone an object in JavaScript, circa 2013, that was a wheel you needed to invent for yourself, as this StackOverflow thread highlights.
There are now better options, and you'd think that people would use them. However, the only thing more "fun" than dealing with code that hasn't caught up with the times is dealing with developers who haven't, and still insist on writing their own versions of standard methods.
const objectReplace = (oldObject, newObject) => {
let keys = Object.keys(newObject)
try {
for (let key of keys) {
oldObject[key] = newObject[key]
}
} catch (err) {
console.log(err, oldObject)
}
return oldObject
}
It's worth noting that Object.entries returns an array containing both the keys and values, which would be a more sensible for this operation, but then again, if we're talking about using correct functions, Object.assign would replace this function.
There's no need to handle errors here, as nothing about this assignment should throw an exception.
The thing that really irks me about this though is that it pretends to be functional (in the programming idiom sense) by returning the newly modified value, but it's also just changing that value in place because it's a reference. So it has side effects, in a technical sense (changing the value of its input parameters) while pretending not to. Now, I probably shouldn't get too hung up on that, because that's also exactly how Object.assign behaves, but dammit, I'm going to be bothered by it anyway. If you're going to reinvent the wheel, either make one that's substantially worse, or fix the problems with the existing wheel.
In any case, the real WTF here is that this function is buried deep in a 15,000 line file, written by an offshore contract team, and there are at least 5 other versions of this function, all with slightly different names, but all basically doing the same thing, because everyone on the team is just copy/pasting until they get enough code to submit a pull request.
Our submitter wonders, "Is there a way to train an AI to not let people type this?"
No, there isn't. You can try rolling that boulder up a hill, but it'll always roll right back down. Always and forever, people are going to write bad code.
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This post originally appeared on The Daily WTF.