modules.md

Modules

Modules are the preferred way to expose application APIs to scripts.

Module Manager

ScriptModuleExportResolverFactory getModuleExportResolver();
void setModuleExportResolver(ScriptModuleExportResolverFactory factory);

ScriptAccess getScriptAccess();
void setScriptAccess(ScriptAccess scriptAccess);

ScriptInternalModule getGlobalModule();
Map<String, ScriptModule> getModules();
ScriptModule getModule(String name);
void addModule(ScriptModule module);
void removeModule(String name);

Every runtime has its own module manager implementation.

Module Types

Type	Interface	Description
Internal	ScriptInternalModule	Java-defined exports.
External	ScriptExternalModule	JavaScript source loaded from file or bytes.

Internal Module

SimpleScriptInternalModule app = new SimpleScriptInternalModule("app");
app.export(new ScriptValueExport("version", "1.0.0"));
script.getModuleManager().addModule(app);

import { version } from "app";
version;

Global Module

Exports in getGlobalModule() are available without import.

Runtime implementations also copy globally registered functions and constants into the global module before compilation.

Use global exports sparingly. Modules are clearer for larger APIs.

Export Types

Export	Description
ScriptFunctionExport	Exports a ScriptFunction; runtime creates a callable wrapper.
ScriptFunctionDefinitionExport	Exports an existing function definition.
ScriptConstantExport	Exports a ScriptConstant.
ScriptValueExport	Exports a Java value, object instance, enum, or Class<?>.

Java Value Exports

module.export(new ScriptValueExport("config", Map.of("mode", "dev")));
module.export(new ScriptValueExport("Service", UserService.class));
module.export(new ScriptValueExport("service", new UserService()));

Access to Java members depends on ScriptAccess.

Copying Modules

ScriptInternalModule.copy copies exports from another internal module.

SimpleScriptInternalModule std = new SimpleScriptInternalModule("std");
std.copy(new StandardScriptModule());
script.getModuleManager().addModule(std);

Copy rejects conflicting exports with the same name and different hash.

Import Syntax

GraalVM supports native module imports through its Scriptify virtual file system.

Rhino supports these top-level forms:

import * as name from "module";
import { value, other as alias } from "module";
import defaultValue from "module";
import "module";

For runtime-specific details, see Runtime Selection and External Modules.