aburtang@lemmy.world to Programmer Humor@lemmy.ml · 5 days agoEvil Oneslemmy.worldimagemessage-square76fedilinkarrow-up1994arrow-down132
arrow-up1962arrow-down1imageEvil Oneslemmy.worldaburtang@lemmy.world to Programmer Humor@lemmy.ml · 5 days agomessage-square76fedilink
minus-squarepooberbee (they/she)@lemmy.mllinkfedilinkarrow-up2arrow-down1·5 days agoYeah, you would get a runtime error calling that member without checking that it exists.
minus-squaremasterspace@lemmy.calinkfedilinkEnglisharrow-up1·edit-211 hours agoBecause 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.
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.