Hello there, I have a Kotlin jvm+wasm project. Now I'm diving a little more in the wasm side, and t...

# multiplatform

[Reginald Louis]

Hello there,

I have a Kotlin jvm+wasm project. Now I'm diving a little more in the wasm side, and this little thing doesn't work. The function doesn't get exported:

@OptIn(ExperimentalJsExport::class)
@JsExport
fun addOne(x: Int): Int = x + 1

Every other aspect of JS Interop work like Kotlin functions with JavaScript code like this one work:

fun setLocalSettings(value: String): Unit = js(
    """{
        localStorage.setItem('settings', value);
}"""

In the doc (https://kotlinlang.org/docs/wasm-js-interop.html#kotlin-functions-with-javascript-code) it's written:
> Kotlin/Wasm functions marked with the @JsExport annotation are visible as properties on a default export of the generated .mjs module. You can then use this function in JavaScript:
>

// JavaScript
> 
> import exports from "./module.mjs"
> 
> exports.addOne(10)

But I don't see this file, well I'm confuse 😛

[William Walker]

Are you running the gradle build tasks to generate that artifact you’re looking for?

[Reginald Louis]

Yes, I'm running the wasmJsBroswerRun

[Reginald Louis]

By reading the code, I stumble on export async function instantiate(imports={}, runInitializer=true) it end like this:

wasmExports = wasmInstance.exports;
    if (runInitializer) {
        wasmExports._initialize();
    }

    return { instance: wasmInstance,  exports: wasmExports };

So I can see that my function are i the wasmExports. By doing some investigation, if I put a breakpoint anywhere in a my *.wasmJs.kt file, I see an intance.exports in the scope in chrome in where the exported functions are.

[Reginald Louis]

If I wrote in the console instance.exports.addOne(5) it work. It is how I should access my exported function in javascript?

[William Walker]

You need to run the Gradle build task to build that minified js file

[Reginald Louis]

Ok I found the solution. I should add that what I was tring to call the exported addOne function in side a js() like this

fun anotherFun() = js(
"""
addOne(5)
"""
)

[Reginald Louis]

It work if I do this:

fun anotherFun() = js(
"""
wasmExports.addOne(5)
"""
)

[Reginald Louis]

So to resume, this work:

@OptIn(ExperimentalJsExport::class)
@JsExport
fun addOne(x: Int): Int = x + 1

fun callingAddOne() = js(
"""
wasmExports.addOne(5)
"""
)