Is it possible to call kotlin's js function with an interpolated string template?

Question

Right now, IntellJ is showing a red squiggly line saying: Argument must be a string constant

private fun fromEnv(name: String) {
    return js("process.env[${name}]") as Unit
}

I've searched but I have not found any similar question.

Solved by @alexey-romanov

It's just as simple as:

private fun fromEnv(name: String) {
    return js("process.env[${name}]") as Unit
}

which compiles to:

function fromEnv(name) {
  var tmp$;
  return typeof (tmp$ = process.env[name]) === 'string' ? tmp$ : throwCCE();
}

Alexey Romanov · Accepted Answer · 2019-12-23T19:01:31.017

3

No, it isn't. But you can just use name in the code argument to js:

private fun fromEnv(name: String) {
     js("process.env[name]")
}

This example is pretty much the same as the use of the variable o in the Inline Javascript section of documentation:

fun jsTypeOf(o: Any): String {
    return js("typeof o")
}

edited Dec 23 '19 at 19:01

answered Dec 23 '19 at 16:18

Alexey Romanov

Thank you! Do you have any reference you can share with this answer? – Richard Domingo Dec 23 '19 at 17:11
Btw, @Alexey Romanov, removing the explicit cast shows a warning: Unsafe implicit cast from dynamic to String. – Richard Domingo Dec 23 '19 at 18:37
1

I've added the reference. Testing at https://try.kotlinlang.org/ I don't get a warning (but do get a wrong warning that `name` is unused), and don't see why it would be a cast to `String` anyway. – Alexey Romanov Dec 23 '19 at 19:04

1 Answers1