Hi, is there a way to instantiate JsArray? Similar...

# webassembly

[aspirew]

Hi, is there a way to instantiate JsArray? Similarly to Int.toJsNumber. I am trying to create a JsArrayJsNumber to check execution of jsExported method locally
Is there a method allowing to multiply JsNumbers directly without having to cast to Int? I am checking how does code perform on matrix multiplication and I didnt want to create overhead with casting

[aspirew]

As for now wasm version performs significantly worse than native kotlin version for 100x100 matrix (69 ms vs 4 ms). I started out from nodejs example. Are there any optimization flags by any chance or something I should remember about? Or should I assume that it's still early stage and shortcomings are expected?

@JsExport
fun execute(matrix1: JsArray<JsNumber>, matrix2: JsArray<JsNumber>, size: Int) {
    val result = MutableList(size * size) { 0.0 }
    for (i in 0 until size) {
        for (j in 0 until size) {
            var sum = 0.0
            for (k in 0 until size) {
                val num1 = matrix1[i * size + k]!!.toInt()
                val num2 = matrix2[k * size + j]!!.toInt()
                sum += num1 * num2
            }
            result[i * size + j] = sum
        }
    }
}

[Artem Kobzar]

@Svyatoslav Kuzmich [JB] ^^

[Svyatoslav Kuzmich [JB]]

It is expected that JsArray is slow, it performs non-inlined Wasm->JS call for each element access. To speed things up, it might be better to copy JsArray into IntArray or DoubleArray just once, and then do a lot of repeated actions on them:

val fasterMatrix1 = IntArray(size) { matrix1[it]!!.toInt() }

[aspirew]

Thanks! Now it has close to native performance 💯