With Node SEA, how to pack node_modules into executable?

Question

This new «Single Executable Applications» feature sounds cool but it's not clear how to use node module packages from SEA application.

I know it mentions assets:

  "assets": {
    "a.jpg": "/path/to/a.jpg",
    "b.txt": "/path/to/b.txt"
  }

But by pointing to entire folder, this doesn't seem to work:

{
  "main": "hello.js",
  "output": "sea-prep.blob",
  "assets": {
    "node_modules": "./node_modules"
  }
}

How to pack node_modules?