What would be the equivalent of `java.text.NumberFormat` when using Wasm based Compose for Web?

# webassembly

[John O'Reilly]

What would be the equivalent of java.text.NumberFormat when using Wasm based Compose for Web?

[eygraber]

I'm doing this to replace java.text.DecimalFormat . There's probably some API that could do something similar for java.text.NumberFormat

[jw]

Call out to Intl, presumably

[John O'Reilly]

Call out to Intl, presumably

do you mean through something like import js.intl.NumberFormat ? That works in Kotlin/JS but not wasm I think

[jw]

That why I said "call out", as in, call into the JS runtime's JS API for Intl

[John O'Reilly]

ah, though something like this? https://github.com/Kotlin/kotlin-wasm-examples/blob/main/compose-jetsnack/common/src/wasmJsMain/kotlin/com/example/jetsnack/ui/utils/formatPrice.kt

[jw]

Yeah. Define whatever subset of the API you need and you should be good.

[John O'Reilly]

Works great, thanks

private external object Intl {
    class NumberFormat(locales: String, options: JsAny) {
        fun format(l: Double): String
    }
}

private fun formatPercentageOptions(): JsAny = js("({ style: 'percent', maximumFractionDigits: 2 })")
private fun formatAsUSDOptions(): JsAny = js("({ style: 'currency', currency: 'USD',})")

internal actual fun Double.formatPercentage(): String {
    val format = Intl.NumberFormat(
        locales = "en-US",
        options = formatPercentageOptions(),
    )
    return format.format(this)
}

internal actual fun Double.formatDollarAmount(): String {
    val format = Intl.NumberFormat(
        locales = "en-US",
        options = formatAsUSDOptions(),
    )
    return format.format(this)
}