How to use the @jscad/modeling.booleans function in @jscad/modeling

/* title      : Chain Hull
// author     : Rene K. Mueller, Moissette Mark
// license    : MIT License
// date       : 2013/04/18
// description: Whosa whatsis suggested "Chain Hull" as described at
//    https://plus.google.com/u/0/105535247347788377245/posts/aZGXKFX1ACN
*/

const { sin, cos } = Math
const { circle } = require('@jscad/modeling').primitives
const { translate, scale } = require('@jscad/modeling').transforms
const { union } = require('@jscad/modeling').booleans
const { hullChain } = require('@jscad/modeling').hulls
const { extrudeLinear } = require('@jscad/modeling').extrusions

const main = () => {
  const shell = []
  const hexagon = []

  for (let i = 0; i < 12; i++) { // -- shell like
    const x = sin(i / 12 * 180) * 10
    const y = cos(i / 12 * 180) * 10
    shell.push(
      translate([x, y, 0], scale(6 - i / 2, circle())) // { center: true }
    )
  }

  const n = 6

/* title      : Stepper Motor
// author     : Derrick Oswald
// license    : MIT License
// description: a simple stepper motor design
// tags: extrusion, extrudeFromSlices, slices
*/

const { circle, cube, cylinder } = require('@jscad/modeling').primitives
const { color } = require('@jscad/modeling').color
const { translate, rotateX } = require('@jscad/modeling').transforms
const { extrudeFromSlices, slice } = require('@jscad/modeling').extrusions
const { mat4 } = require('@jscad/modeling').math
const { union, intersect } = require('@jscad/modeling').booleans
const { sqrt } = Math
const { degToRad } = require('@jscad/modeling').math

const getParameterDefinitions = () => {
  return ([
    { name: 'motorBody_len', type: 'float', initial: 47.5, step: 0.5, caption: 'Motor length' },
    { name: 'motorBody_width', type: 'float', initial: 42.0, step: 0.5, caption: 'Motor width' },
    { name: 'motorBody_chamfer', type: 'float', initial: 5.0, step: 0.1, caption: 'Motor chamfer' },

    { name: 'motorCap_len', type: 'float', initial: 8.0, step: 0.1, caption: 'Motor cap length' },
    { name: 'motorCap_thickness', type: 'float', initial: 1.0, step: 0.1, caption: 'Motor cap thickness' },
    { name: 'motorCap_chamfer', type: 'float', initial: 2.5, step: 0.1, caption: 'Motor cap chamfer' },

    { name: 'shaft_len', type: 'float', initial: 22.0, step: 0.5, caption: 'Shaft length' },
    { name: 'shaft_radius', type: 'float', initial: 2.5, step: 0.1, caption: 'Shaft radius' },

/* title      : Expand
// author     : OpenSCAD.org, adapted by Rene K. Mueller
// license    : MIT License
// description: expand() function
*/

const { geom2, geom3, line2, path2 } = require('@jscad/modeling').geometry
const { cuboid, cylinder } = require('@jscad/modeling').primitives
const { translate, scale } = require('@jscad/modeling').transforms
const { union, difference } = require('@jscad/modeling').booleans
const { expand } = require('@jscad/modeling').expansions
const { color } = require('@jscad/modeling').color

const main = () => {
  // you can expand 2d paths
  const points = [
    [10, 0],
    [9.510565162951535, 3.090169943749474],
    [8.090169943749475, 5.877852522924732],
    [5.877852522924732, 8.090169943749475],
    [3.0901699437494745, 9.510565162951535],
    [6.123233995736766e-16, 10]
  ]
  const path2Example = color('black',
    path2.fromPoints({ }, points) // it also works with ccw points ie points.reverse()
  )