The is the test case - https://github.com/rkbalgi/iso4k-mp/blob/main/src/jsTest/kotlin/SpecTestsJs.kt#L17
Note the use of null-assertion (children!!) which is not required. However, changing this to children? causes the test to fail
TypeError: Cannot read properties of undefined (reading ‘length’)
If you look at line which causes the error
var $receiver_0 = first$result;
var tmp$_1, tmp$_2;
if ((tmp$_1 = $receiver_0.children) != null) {
var tmp$_3;
for (tmp$_3 = 0; tmp$_3 !== tmp$_1.length; ++tmp$_3) {
var element_0 = tmp$_1[tmp$_3];
println(element_0.name);
}
}
var $receiver_1 = tmp$_2;
var first$result_0;
first$break: do {
var tmp$_4;
for (tmp$_4 = 0; tmp$_4 !== $receiver_1.length; ++tmp$_4) { // This line
$receiver_1 is null (because tmp$_2 is null which is never assigned to)
The same test on JVM target works fine - https://github.com/rkbalgi/iso4k-mp/blob/main/src/jvmTest/kotlin/io/github/rkbalgi/iso4k/SpecTestsJvm.kt#L17
Reproducible both on 1.6.21 and 1.7.10