this post was submitted on 20 Dec 2024
988 points (97.1% liked)
Programmer Humor
32710 readers
1240 users here now
Post funny things about programming here! (Or just rant about your favourite programming language.)
Rules:
- Posts must be relevant to programming, programmers, or computer science.
- No NSFW content.
- Jokes must be in good taste. No hate speech, bigotry, etc.
founded 5 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Yeah, you would get a runtime error calling that member without checking that it exists.
Because that object is of a type where that member may or may not exist. That is literally the exact same behaviour as Java or C#.
If I cast or type check it to make sure it's of type Bar rather than checking for the member explicitly it still works:
And when I cast it to Foo it throws a compile time error, not a runtime error:
I think your issues may just like in the semantics of how Type checking works in JavaScript / Typescript.