Updating Three.js Closure Compiler Build path to ES6 Modules.

Hello,

This month we’ve moved three.js code base to ES6 Modules (https://github.com/mrdoob/three.js/pull/9310) and I’ve been trying to port the current Closure Compiler-based build path.

I’m having a really hard time finding command line examples of how to handle ES6 Modules.

As a simple reduced test case I’m doing this:

I have these two files: https://gist.github.com/mrdoob/7d75270a22b9d62da2e1e991ef846188

I run this:

java -jar closure-compiler-v20160713.jar --warning_level=VERBOSE --language_in=ECMASCRIPT6_STRICT --js index.js --js_output_file test.js

And I get this:

WARNING - Failed to load module "./Layers.js"

index.js:1: ERROR - required "module$Layers_js" namespace never provided
import { Layers } from './Layers.js';
^

This code compiles just fine in http://rollupjs.org/. Any ideas…?

Thanks in advance!

[MatrixFrog]

The way we translate ES6 modules, was designed with advanced compilation in mind. If you can switch to advanced mode that would be ideal. See https://developers.google.com/closure/compiler/docs/api-tutorial3

If not, there was some discussion recently about making ES6 modules work better with simple mode but I don’t know that it will happen particularly soon.

[mkeblx]

Yes… you do need to omit the file extension in index.js: import { Layers } from './Layers';

And, for warning:

/**
 * @constructor
 */
function Layers() {

    this.mask = 1;

}

And can use wildcard.

java -jar closure-compiler-v20160713.jar --warning_level=VERBOSE --language_in=ECMASCRIPT6_STRICT --js **.js --js_output_file test.js