Possibility of replacing J2V8 with Javet

[daredevil2033]

J2V8 is severely outdated and is no longer maintained. The unofficial v6.2.0 build doesn't support Node.js which, if I understood correctly, is needed for viz.js but already provides a significant perfomance improvement. The tradeoff would be losing Mac support but at this point wouldn't GraalJS + GraalVM provide a similar perfomance compared to the 2016 verison of V8?

[lihaoyi]

Here's an implementation I ended up using to integrate Javet

class V8JavascriptEngine() extends AbstractJavascriptEngine {
  val LOG = LoggerFactory.getLogger(classOf[V8JavascriptEngine])
  val v8Runtime: V8Runtime = V8Host.getV8Instance().createV8Runtime()
  LOG.info("Starting V8 runtime...")
  LOG.info("Started V8 runtime. Initializing javascript...")
  val resultHandler = new ResultHandler
  val javetStandardConsoleInterceptor = new JavetStandardConsoleInterceptor(v8Runtime)
  javetStandardConsoleInterceptor.register(v8Runtime.getGlobalObject)

  class ResultHandlerInterceptor(resultHandler: ResultHandler){
    @V8Function
    def result(s: String) = resultHandler.setResult(s)

    @V8Function
    def error(s: String) = resultHandler.setError(s)

    @V8Function
    def log(s: String) = resultHandler.log(s)
  }
  val v8ValueObject = v8Runtime.createV8ValueObject
  v8Runtime.getGlobalObject.set("resultHandlerInterceptor", v8ValueObject)
  v8ValueObject.bind(new ResultHandlerInterceptor(resultHandler))

  v8Runtime.getExecutor(
    "var result = resultHandlerInterceptor.result; " +
      "var error = resultHandlerInterceptor.error; " +
      "var log = resultHandlerInterceptor.log; "
  ).execute()

  LOG.info("Initialized javascript.")

  override protected def execute(js: String): String = {
    v8Runtime.getExecutor(js).execute()
    resultHandler.waitFor
  }

  override def close(): Unit = v8Runtime.close()
}