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package advanced
import org.scalajs.dom
import org.scalajs.dom.XMLHttpRequest
import org.scalajs.dom.extensions.{Ajax, KeyCode}
import scala.collection.mutable
import scala.concurrent.Future
import scala.scalajs.js
import scalatags.JsDom.all._
import scala.scalajs.js.annotation.JSExport
import scala.scalajs.concurrent.JSExecutionContext.Implicits.runNow
@JSExport
object Futures {
def main(container: dom.HTMLDivElement,
handle: (Seq[String], dom.HTMLDivElement) => Unit) = {
val myInput = input(value:="London,Singapore,Berlin,New York").render
val output = div.render
myInput.onkeyup = (e: dom.KeyboardEvent) => {
if (e.keyCode == KeyCode.enter){
handle(myInput.value.split(','), output)
}
}
container.appendChild(
div(
i("Press Enter in the box to fetch temperatures "),
myInput,
output
).render
)
}
def urlFor(name: String) = {
"http://api.openweathermap.org/data/" +
"2.5/find?mode=json&q=" +
name
}
def parseTemp(text: String) = {
val data = js.JSON.parse(text)
val kelvins = data.list
.pop()
.main
.temp
.asInstanceOf[Double]
kelvins - 272.15
}
def formatResults(output: dom.HTMLElement, results: Seq[(String, Double)]) = {
output.innerHTML = ""
output.appendChild(ul(
for((name, temp) <- results) yield li(
b(name), " - ", temp.toInt, "C"
)
).render)
}
@JSExport
def main0(container: dom.HTMLDivElement) = {
def handle0(names: Seq[String], output: dom.HTMLDivElement) = {
val results = mutable.Buffer.empty[(String, Double)]
for(name <- names){
val xhr = new XMLHttpRequest
xhr.open("GET", urlFor(name))
xhr.onload = (e: dom.Event) => {
val temp = parseTemp(xhr.responseText)
results.append((name, temp))
if (results.length == names.length){
formatResults(output, results)
}
}
xhr.send()
}
}
main(container, handle0)
}
@JSExport
def main1(container: dom.HTMLDivElement) = {
def handle1(names: Seq[String], output: dom.HTMLDivElement) = {
val results = mutable.Buffer.empty[(String, Double)]
for{
name <- names
xhr <- Ajax.get(urlFor(name))
} {
val temp = parseTemp(xhr.responseText)
results.append((name, temp))
if (results.length == names.length){
formatResults(output, results)
}
}
}
main(container, handle1)
}
@JSExport
def main2(container: dom.HTMLDivElement) = {
def handle2(names: Seq[String], output: dom.HTMLDivElement) = {
val futures = for(name <- names) yield{
Ajax.get(urlFor(name)).map( xhr =>
(name, parseTemp(xhr.responseText))
)
}
for(results <- Future.sequence(futures)){
formatResults(output, results)
}
}
main(container, handle2)
}
}
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