ES Modules

Loading multiple files with native import resolution

nx.js resolves native ES module import statements at runtime, so you can ship an unbundled, multi-file app or lazy-load modules on demand with dynamic import().

Tip

For distribution, bundling your app into a single file with esbuild is still recommended. Native imports are additive — they enable unbundled multi-file apps, the REPL, and app-level lazy loading.

Static imports

Both static import and top-level await are supported. Specifiers are resolved as URLs relative to the importing module:

romfs/main.js

import { greet } from './greet.js';
import { CONFIG } from '/config.js'; // absolute path

greet(CONFIG.name);

romfs/greet.js

export function greet(name) {
  console.log(`Hello, ${name}!`);
}

Dynamic imports

await import() works too, for lazy-loading code only when needed:

async function onLevelStart() {
  const { loadLevel } = await import('./levels/level1.js');
  loadLevel();
}

Resolution rules

Module specifiers are resolved against the importing module's URL:

Specifier	Example	Supported
Relative	`./util.js`, `../lib/x.js`	✅
Absolute path	`/config.js`	✅
Absolute URL	`romfs:/x.js`, `sdmc:/x.js`, `nxjs:/x.js`, `file:/x.js`	✅
Bare specifier	`react`, `lodash`	❌ (throws)
Remote URL	`https://…`, `data:…`	❌ (not yet supported)

There is no node_modules resolution or import maps — bare specifiers (like react) throw. Use a bundler if you depend on npm packages.
Resolution is synchronous, so only mounted filesystem schemes work (romfs:, sdmc:, nxjs:, file:). Remote http(s):/data: imports are not supported.
JSON and other asset module types are not yet supported.

`import.meta`

Each module has an accurate import.meta:

console.log(import.meta.url);  // the module's resolved URL
console.log(import.meta.main); // true only for the entrypoint

Module cache & cycles

Modules are cached by their resolved URL, so a shared dependency imported through multiple paths resolves to a single instance (giving referential stability), and import cycles are handled correctly.