如何使用Nashorn从Java方法返回真正的JavaScript数组？

Question

I'm writing an API to be used by some JavaScript code. Some of the methods in this API should return a real JavaScript array. Unfortunately, this doesn't work:

// MyApi.java
public class MyApi {
    String[] returnsJavaArray();

    List<String> returnsJavaList();
}

// MyScript.js
var api = getMyApi();
var strings = api.returnsJavaArray(); // Returns some kind of proxy
strings = api.returnsJavaList(); // Also a proxy

While the proxies support basic things like strings[i] , I need them to be actual arrays in order to use some Array polyfills. What's the best way to do this in Nashorn?

My only idea so far is to write a JavaScript wrapper of the whole MyApi and wrap the results with Java.from(api.returnsJavaArray()) but that's pretty tedious.

Answer 1

You should make you API return a string of js. Then, in your js file, you can call

eval(stringOfJsReturnFromServer); 

To make your script run