Equivalent of Ruby's "require" in Javascript

Question

How do you "require" another file into the existing file in Javascript? Is there anything similar to Ruby's "require" or "load"?

> Note: I'm using JS in server (Rhino)

Reason: I just need to access the methods in the other JS files.

Update: This works only when executing it from cmd line. When I try to call it programatically it fails. Here's my code: http://pastie.org/1240495

Answer 1

In Rhino shell, you can should be able to use load(), which is a predefined global method:

load([filename, ...])

Load JavaScript source files named by string arguments. If multiple arguments are given, each file is read in and executed in turn.

Answer 2

To use the load function in js embedded from Java, you must first expose it in on the scripting context. There's probably a way to do it from Java, but you can do it using js as well.

Disclaimer: this solution uses source code taken from an Apache-licensed project I have been working on. You can see the original source file here.

This js file sets up your global variables, and lives in a file named setupglobals.js:

var shell = org.mozilla.javascript.tools.shell.Main;
var args = ["-e","var a='STRING';"];
shell.exec(args);

var shellGlobal = shell.global;

//grab functions from shell global and place in current global
load=shellGlobal.load;
print=shellGlobal.print;
defineClass=shellGlobal.defineClass;
deserialize=shellGlobal.deserialize;
doctest=shellGlobal.doctest;
gc=shellGlobal.gc;
help=shellGlobal.help;
loadClass=shellGlobal.loadClass;
quit=shellGlobal.quit;
readFile=shellGlobal.readFile;
readUrl=shellGlobal.readUrl;
runCommand=shellGlobal.runCommand;
seal=shellGlobal.seal;
serialize=shellGlobal.serialize;
spawn=shellGlobal.spawn;
sync=shellGlobal.sync;
toint32=shellGlobal.toint32;
version=shellGlobal.version;
environment=shellGlobal.environment;

Here is your original Java host file, now augmented to evaluate setupglobals.js before any other scripts:

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import org.mozilla.javascript.*;

public class RhinoRunner {
    public static void main(String args[]) throws IOException 
    {
        BufferedReader script = new BufferedReader(new FileReader("setupglobals.js"));
        BufferedReader script2 = new BufferedReader(new FileReader("example.js"));
        Context context = Context.enter();
        try {
            ScriptableObject scope = context.initStandardObjects();
            context.evaluateReader(scope, script, "script", 1, null);
            context.evaluateReader(scope, script2, "script2", 1, null);
            Function fct = (Function)scope.get("abc", scope);
            Object result = fct.call(context, scope, scope, new Object[] {2, 3});
            System.out.println(Context.jsToJava(result, int.class));
        } 
        finally 
        {
            Context.exit();
        }
    }
}

Here is your example.js, now augmented to use the global load function to load the file hello.js:

function abc(x,y) 
{
    return x+y 
}

load("hello.js")

And finally, here is hello.js:

print("hello world!")

When executed, RhinoRunner prints the following:

hello world!
5