Attach modal to Sketch document

attachModal.js

let window = document.sketchObject.window()
let fiber = coscript.createFiber()

let alert = NSAlert.alloc().init()
alert.addButtonWithTitle("OK")
alert.addButtonWithTitle("Cancel")
alert.setMessageText("This is the message text")
alert.setInformativeText("This is some extra informative text")
alert.setAlertStyle(NSAlertStyleWarning)

alert.beginSheetModalForWindow_completionHandler(window,__mocha__.createBlock_function(
  'v16@?0q8', 
  (returnCode) => {
    try {
      handleReturnCode(returnCode)
    } catch (err) {
      console.error(err)
    }
    NSApp.endSheet(alert)
    if (fiber) {
      fiber.cleanup()
    }
  })
)

function handleReturnCode(returnCode) {
  if (returnCode == NSAlertFirstButtonReturn) {
    console.log("Success")
  } else {
    console.log("nope")
  }
}