Why is an error reported here? It works fine in js

# getting-started

[Ayla]

Why is an error reported here?
It works fine in js

[Vampire]

Because Kotlin is not JS

[Vampire]

Ohter language, other rules.

[Vampire]

Even if you in the end cross-compile to JS

[ephemient]

the name isn't bound until after the declaration. this allows for things like

fun foo(x: Int?) {
    val x: Int = x ?: default

the x on the right-hand side refers to the x from the outer scope, the left-hand side x doesn't exist yet.

[Vampire]

Not that you should do such shadowing 😄

[ephemient]

also it would be unsafe in Kotlin to allow that, for example

val x = run { x }

[ephemient]

to write a self-referential lambda, you need to use an object expression,

val obs = object : () -> Unit {
    override fun invoke() {
        signalApplyCallback = this
    }
}

note that the name obs still isn't bound yet, but you can refer to the lambda itself as this

[Ayla]

Thanks