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dynamictypeskotlinkotlin-interop

How can I declare a function parameter that can be a string or a function, in Kotlin?

In the following function, I want to pass to it attributes for a html tag. These attributes can be strings (test("id", "123")) or functions (test("onclick", {_ -> window.alert("Hi!")})): 

fun test(attr:String, value:dynamic):Unit {...}

I tried to declare the parameter value as Any, the root type in Kotlin. But functions aren't of type Any. Declaring the type as dynamic worked, but

  • dynamic isn't a type. It just turns off typing checking for the parameter.
  • dynamic only works for kotlin-js (Javascript).

How can I write this function in Kotlin (Java)? How do function types relate to Any? Is there a type that includes both function types and Any?

Solution

  • You could just overload the function:

    fun test(attr: String, value: String) = test(attr, { value })

fun test(attr: String, createValue: () -> String): Unit {
    // do stuff
}