Play 2.5.3 ScriptException：TypeError：无法在第1行的<eval>中调用undefined

Question

我成功下载并成功运行了项目here，但在升级到Play 2.5.3后它又崩溃了。有帮助吗？错误发生在最后一条指令

上

package controllers

import javax.inject._
import play.api._
import play.api.http._
import play.api.mvc._
import play.twirl.api.Html
import java.io.FileReader
import javax.script.ScriptEngineManager

@Singleton
class HomeController @Inject()(webJarAssets: WebJarAssets) extends Controller {

  /**
   * Create an Action to render an HTML page with a welcome message.
   * The configuration in the `routes` file means that this method
   * will be called when the application receives a `GET` request with
   * a path of `/`.
   */
  def index2 = Action {
    Ok(views.html.index("Your new application is ready.",webJarAssets))
  }

  def index = Action {
    // Pass 'null' to force the correct class loader. Without passing any param,
    // the "nashorn" JavaScript engine is not found by the `ScriptEngineManager`.
    //
    // See: https://github.com/playframework/playframework/issues/2532
    val engine = new ScriptEngineManager(null).getEngineByName("nashorn")

    if (engine == null) {
      BadRequest("Nashorn script engine not found. Are you using JDK 8?")
    } else {
      // React expects `window` or `global` to exist. Create a `global` pointing
      // to Nashorn's context to give React a place to define its global
      // namespace.
      engine.eval("var global = this;")

      // Define `console.log`, etc. to send messages to Nashorn's global `print`
      // function so the messages are written to standard out.
      engine.eval("var console = {error: print, log: print, warn: print};")

      // Evaluate React and the application code.
      engine.eval(new FileReader("target/web/web-modules/main/webjars/lib/react/react-with-addons.js"))
      engine.eval(new FileReader("target/web/public/main/javascripts/components/App.js"))

      Ok(views.html.main("React on Play",webJarAssets) {
        play.twirl.api.Html(engine.eval("React.renderToString(React.createElement(App));").toString)
      })
    }
  } 
}