Hi, is it possible to have a default value for a g...
# getting-starteda
Ayfri
08/08/2021, 2:42 AMHi, is it possible to have a default value for a generic type of a class ?
Like that code in TypeScript :
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class Test<T = string> {
readonly thing: T
}
const a = new Test() // this works
const b = new Test<number>() // this toon
Nathan Bedell
08/08/2021, 2:59 AMHi, unfortunately it looks like this hasn't been implemented yet. I'd love to see something like this feature though!
😕 1
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James Whitehead
08/08/2021, 4:31 AMIf you are saying
TString Copy code
class Test<T : String> {}d
Dave K
08/08/2021, 4:47 AMIt looks like they’re wanting to omit the <> entirely and have the default implication be that it’s a string, but also support other things explicitly such as Number
Dave K
08/08/2021, 4:52 AMCould you not do
fun Test() = Test<String>()
blob open mouth 1
Dave K
08/08/2021, 4:57 AMwith constructor arg or not https://pl.kotl.in/mJLv3yyUg
Though with the lateinit var has to have a non nullable value and also isn’t read only. However since the example didn’t have a constructor argument I wasn’t sure what the intended use was
Dave K
08/08/2021, 5:10 AMIf you’re using a constructor argument then the type may not even be necessary to specify explicitly https://pl.kotl.in/pfl7VDG97
a
Ayfri
08/08/2021, 2:21 PMThis is nice thanks !
Also is there a workaround for interfaces (with also a generic type an some properties that have that type) ?
d
diesieben07
08/08/2021, 2:29 PMTypealiases can do this:
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class Test<T> { }
typealias DefaultTest = Test<String>👍 1
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