6
Almost had to mark this one NSFW (sh.itjust.works)
submitted 9 months ago* (last edited 9 months ago) by stale_cheetos@sh.itjust.works to c/programming_horror@programming.dev
5 comments fedilink hide all child comments

For those unfamiliar with JS: subValue (the first argument in the forEach callback) is the value contained at arr[index].

you are viewing a single comment's thread
view the rest of the comments
[-] CodexArcanum@lemmy.world 11 points 9 months ago* (last edited 9 months ago)

Trivially, could also just be a retVal.map(self.cleanupMetadata)

[-] kevincox@lemmy.ml 16 points 9 months ago* (last edited 9 months ago)

But it can't! (Maybe)

calling map(obj.func) will pass func but won't set the this parameter correctly. If the called method uses this you will have a bad time.

The code you actually want would be retval.map(v => self.cleanupMetadata(v)) or the old-skool retval.map(self.cleanupMetadata.bind(self)).

Also the first version reuses the Array which may be important, but even if not will likely result in better performance. (Although this is likely mitigated by making the array polymorphic depending on the return type of cleanupMetadata and the overhead of forEach vs map.)

Wow, isn't JS a great language.

this post was submitted on 23 Jan 2024
6 points (66.7% liked)

Programming Horror

1634 readers
1 users here now

Welcome to Programming Horror!

This is a place to share strange or terrible code you come across.

For more general memes about programming there's also Programmer Humor.

Looking for mods. If youre interested in moderating the community feel free to dm @Ategon@programming.dev

Rules

Credits

founded 1 year ago
MODERATORS
Vacant@programming.dev