Sharing this idea and also calling to discuss improvements to it.
Even ideas how jscad could be improved to better facilitate use case like this are welcome.

Very often when creating thins for 3d print I have multiple parts, so in time I have created a sort of template I like to use. Even if I have single piece I tend to split design in few parts to more easily handle it.

This is the latest iteration that solves few issues for me

• parameter definition to select a part is generated automatically
• no need to declare configurable parameters in each function ( func that creates a part)
• can reuse one part in another part

const jscad = require('@jscad/modeling')
const {sphere, cube} = jscad.primitives 
const {translate} = jscad.transforms

// all of the functions that generate parts will see the parameters without declaring them explicitly
const main = ({//@jscad-params
  size=10, // {type:'slider'}
  part,
}, getParams)=>{

  // UTILITY placeholder for part generator functions
  const parts = {}

  // CTRL+R in vscode works just fine
  parts.Sample_Cube = ()=>cube({size})

  parts.Sample_Sphere = ()=>{
    return sphere({radius:size/2})
  }

  // parts can easily be combined
  parts.Assembly = ()=>([
    // jump to definition in vscode (ALT+click) works
    parts.Sample_Cube(),
    translate([size+5,0,0], parts.Sample_Sphere()),
  ])

  /*********************** UTILITY below is just utility code. do not change **************** */

  // we were called by getParameterDefinitions so we need to provide list of parts
  if(getParams === true){
    const values = Object.keys(parts)
    return {values, initial: values[0]}
  }

  // make sure we always call one of the functions
  if(!parts[part]) part = Object.keys(parts)[0]
  return parts[part]()
}

const getParameterDefinitions = ()=>[{ name: 'part', caption:'Part', type: 'choice', ...main({}, true)}]

module.exports = {main, getParameterDefinitions}