KotlinJS Fetch with coroutines

request.kt

package app

import kotlinx.coroutines.experimental.await
import org.w3c.fetch.*
import kotlin.browser.window
import kotlin.js.json

class FetchError(message: String, status: Number, response: dynamic) : Error(message)

suspend fun makeError(res: Response): FetchError {
    try {
        val errorResponse: dynamic = res.json().await()
        return FetchError("Request failed", res.status, errorResponse)
    } catch (e: Exception) {
        val errorResponse = res.text().await()
        return FetchError("Request failed", res.status, errorResponse)
    }
}

suspend fun <T> request(url: String, method: String = "GET", body: dynamic = null): T {
    val res = window.fetch(url, object : RequestInit {
        override var method: String? = method
        override var body: dynamic = body
        override var headers: dynamic = json("Accept" to "application/json")
    }).await()


    return if (res.ok) res.json().await() as T else throw makeError(res)
}

usage.kt

fun main(args: Array<String>) {
    launch {
      val loadedUser = request<User>("https://a2pi.github.com/users/huston007")
      console.log(loadedUser)
    }
}