Anyone knows why `org.w3c.files.File.lastModified` it is declared as an `Int` in Kotlin? It returns ...

# javascript

[Tóth István Zoltán]

Anyone knows why org.w3c.files.File.lastModified it is declared as an Int in Kotlin? It returns the wrong value and I think it should be a Long. Also, if I use kotlinx.datetime.Instant.fromEpochMilliseconds(file.lastModified.toLong()) the web browser hangs.

[Tóth István Zoltán]

At the end I used this workaround. It's ugly but works, let me know if there is a better way, I would be thankful.

val lastModified = (js("file.lastModified.toString()") as String).toLongOrNull()
if (lastModified != null) Instant.fromEpochMilliseconds(lastModified.toLong())

[Mike Dawson]

I think the file.lastModified property is a Javascript number type :

Integers can only be represented without loss of precision in the range -2^53 + 1 to 2^53 - 1, inclusive (obtainable via Number.MIN_SAFE_INTEGER and Number.MAX_SAFE_INTEGER), because the mantissa can only hold 53 bits (including the leading 1).

As per: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number

[Mike Dawson]

In Kotlin/JS Long is handled using a Wrapper class, whereas other primitives use the JS native Number

[turansky]

It's JsLong :)

[turansky]

Latest declarations you can find in kotlin-browser

[turansky]

https://github.com/JetBrains/kotlin-wrappers/blob/5f830a51baeb5580f7f8a023709c4030df042272/kotlin-browser/src/jsMain/generated/web/file/File.kt#L21