when using babel for es6, what's the recommended way to get node_modules into _build?

In the simple es6 example, the settings.yml

`build: TARGET={target} npm run build`

and the build script is as follows:

`"build": "babel *.js --out-dir $TARGET"`

This doesn't take into account node_modules. I've added some additional dependencies that I need to be included in node_modules in the _build directory. What's the recommended approach to do this?

Thanks!

Start with the simple ES6 example's settings.yml and its npm build script, then trace how the _build directory is assembled. Determine how the requested dependencies should be included under _build/node_modules, and verify that the resulting build contains them alongside the transpiled files.

Written by the indexing model from the issue text.