◀Table of Contents

GraalVM JavaScript and Node.js Runtime

GraalVM provides an ECMAScript-compliant runtime to execute JavaScript and Node.js applications. It is fully standard compliant, executes applications with high performance, and provides all benefits from the GraalVM stack, including language interoperability and common tooling. This reference documentation provides information on available JavaScript engine configurations, the Node.js runtime, the ScriptEngine implementation, multithreading support details, possible embedding scenarios, and more. To migrate the code previously targeted to the Nashorn or Rhino engines, migration guides are available.

Getting Started

As of GraalVM for JDK 21, the JavaScript (GraalJS) and Node.js runtimes are available as standalone distributions. Two standalone language runtime options are available for both Oracle GraalVM and GraalVM Community Edition: a Native Image compiled native launcher or a JVM-based runtime (included). To distinguish between them, the GraalVM Community Edition version has the suffix -community in the name: graaljs-community-<version>-<os>-<arch>.tar.gz, graalnodejs-community-<version>-<os>-<arch>.tar.gz. A standalone that comes with a JVM has a -jvm suffix in a name.

Navigate to GitHub releases and select a desired standalone for your operating system.
Unzip the archive:
Note: If you are using macOS Catalina and later, first remove the quarantine attribute:
```
 sudo xattr -r -d com.apple.quarantine <archive>.tar.gz
```
Unzip:
```
 tar -xzf <archive>.tar.gz
```
Alternatively, open the file in the Finder.

Check the version to see if the runtime is active:

 ./path/to/bin/js --version

 ./path/to/bin/node --version

Running JavaScript

Use the js launcher to run plain JavaScript (ECMAScript) code:

js [options] [filename...] -- [args]

Running Node.js

The Node.js standalone provides node and npm launchers.

Use the node utility to execute Node.js applications:

node [options] [filename] [args]

The npm command is equivalent to the default Node.js command and supports all Node.js APIs.

Install the colors and ansispan packages using npm install as follows:
```
 npm install colors ansispan
```
After the packages are installed, you can use them from your application.

Add the following code snippet to a file named app.js and save it in the same directory where you installed the Node.js packages:

 const http = require("http");
 const span = require("ansispan");
 require("colors");

 http.createServer(function (request, response) {
     response.writeHead(200, {"Content-Type": "text/html"});
     response.end(span("Hello Graal.js!".green));
 }).listen(8000, function() { console.log("Graal.js server running at http://127.0.0.1:8000/".red); });

 setTimeout(function() { console.log("DONE!"); process.exit(); }, 2000);

Execute it on GraalVM using the node command as follows:
```
 node app.js
```

For more information about running Node.js, go to Node.js Runtime. The Node.js functionality is available when an application is started from the node binary launcher. Certain limits apply when launching a Node.js application or accessing NPM packages from a Java context, see Node.js vs. Java Script Context.

Interoperability with Java

To embed JavaScript in a Java host application, enable JavaScript by adding it as a project dependency. Below is the Maven configuration for a JavaScript embedding:

<dependency>
    <groupId>org.graalvm.polyglot</groupId>
    <artifactId>polyglot</artifactId>
    <version>${graalvm.version}</version>
</dependency>
<dependency>
    <groupId>org.graalvm.polyglot</groupId>
    <artifactId>js</artifactId>
    <version>${graalvm.version}</version>
    <type>pom</type>
</dependency>

It enables the Oracle GraalVM JavaScript runtime by default. Use js-community if you need the artifact built on top of GraalVM Community Edition.

To access Java from JavaScript, use Java.type, as in the following example:

node
> var BigInteger = Java.type('java.math.BigInteger');
> console.log(BigInteger.valueOf(2).pow(100).toString(16));
10000000000000000000000000

Vice versa, you can execute JavaScript from Java by embedding the JavaScript context in the Java program:

import org.graalvm.polyglot.*;
import org.graalvm.polyglot.proxy.*;

public class HelloPolyglot {

    static String JS_CODE = "(function myFun(param){console.log('hello '+param);})";

    public static void main(String[] args) {
        System.out.println("Hello Java!");
        try (Context context = Context.create()) {
            Value value = context.eval("js", JS_CODE);
            value.execute(args[0]);
        }
    }
}

By wrapping the function definition (()), you return the function immediately. The source code unit can be represented with a String, as in the example, a file, read from URL, and other means.

This way you can evaluate JavaScript context embedded in Java, but you will not be able to call a function and set parameters in the function directly from the Java code.

The Node.js runtime cannot be embedded into a JVM but has to be started as a separate process.

For example, save this code as app.js:

var HelloPolyglot = Java.type("HelloPolyglot");

HelloPolyglot.main(["from node.js"]);

console.log("done");

Then run it:

node --vm.cp=. app.js
Hello Java!
hello from node.js
done

Both Node.js and JVM then run in the same process and the interoperability works using the same Value classes as above.

Learn more about language interoperability in the Java Interoperability guide.

Further documentation

For additional information, see the following documentation.

Using GraalVM JavaScript:

Legacy environments:

Node.js support: