How to transform literal function into AST using Babel

Question

I'm trying to update a JS configuration object using Babel. For this, I created a Babel plugin that is used this way:

const transform = require('@babel/standalone').transform


const newCode = transform(code, {
  plugins: [
    [
      myBabelPlugin, {
        scripts: {
          action: 'create:merge',
          value: ['path/to/my/script.js']
        },
        someFunc: {
            action: 'create',
            function a(arg) { return true; }
        }
      }
    ]
  ]
}).code

Internally, it calls a toAst function that iterates over literal elements and returns them as AST. I managed to somewhat make it work for functions but I'm looking for a better way to handle functions - whether they're anonymous, arrow functions, etc.

Current "function to AST" function

if (typeof elem === 'function') {
  const ast = babylon.parse(elem.toString(), {
    plugins: [
      babelPluginTransformRuntime,
      babelPluginTransformArrowFunction
    ]
  })
  const { params, body } = ast.program.body[0]
  return t.functionExpression(
    null,
    params,
    body
  )
}

The reason why I'm doing this is that returning the program body would return something like this:

const config = {
  elem: function () {
    function myFunction() {
      ...
    }
  }
}

But it feels really hacky. It also breaks with anonymous functions. Any clue on what's happening or even code would be greatly appreciated..

Thanks ✌️