Kotlin JS - string to number conversion?

Question

How to do String to number conversion in Kotlin JS app. I am Using the following code and having some trouble converting from the HTMLInputElement value to double.

fun c2f(self: Any) {
   console.log("Self object: ${self} ")
   val celsius = document.getElementById("celcius")?.getAttribute("value") as Double
   val fahrenheit = celsius * 1.8 + 32
   console.log("Fahrenheit value: ${fahrenheit} ")
   window.alert("Celcius (${celsius}) -> Fahrenheit (${fahrenheit}) ")
 }

Also i am not seeing any toDouble() function on String class as in the case of JVM app.

There is String.toDouble(): Double function in stdlib on JVM (github.com/JetBrains/kotlin/blob/master/libraries/stdlib/src/…). Note that it is an extension function, so it is not in the String class. You can find it easily via the code completion. More on extensions: kotlinlang.org/docs/reference/extensions.html — voddan
– voddan, Commented Jun 19, 2015 at 9:25

Suresh · Accepted Answer · 2015-06-19 00:32:34Z

2

Answering my own question as this would be helpful for somebody.

You can use the kotlin.js top level parse functions for string <-> Number conversion.

fun parseInt(s: String, radix: Int = 10): Int
fun safeParseInt(s : String) : Int?
fun safeParseDouble(s : String) : Double?

answered Jun 19, 2015 at 0:32

Suresh

1,9571 gold badge18 silver badges22 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

voddan Over a year ago

I think it is a bug in Kotlin JS API - String.toDouble() must be available for all backends. Fill free to create a report.

bashor Over a year ago

@SureshG of course you can use these functions until KT-4497 not fixed, but toInt, toDouble etc are more kotlinish :)

bashor Over a year ago

Some possible implementations of toDouble You can find here

tomschrot · Accepted Answer · 2018-11-07 10:40:37Z

0

Simply use the String.toXXX() functions, e.g.

val n = "1"
val m = 2 + n.toInt()

val x = "1.1"
val y = 2.0 + x.toFloat()

etc.

answered Nov 7, 2018 at 10:40

tomschrot

2591 gold badge2 silver badges5 bronze badges

Collectives™ on Stack Overflow

Kotlin JS - string to number conversion?

2 Answers 2

3 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related