Do I need paper-jsdom-canvas to use the simplify method in paper.js from nodejs?

Question

I'm trying to simplify a hand-drawn path using paper.js' excellent path.simplify method to generate smooth curves after the user finishes drawing. As this is for a non HTML output (TV Telestration) I'm trying to create a microservice in nodejs to take the points and output the control points of the resulting simplified curves.

I tried using paper-jsdom and the method works and doesn't complain but always outputs a single segment with zero coords in all points. I wonder if I'm supposed to be using paper-jsdom-canvas instead to get the appropriate output.

Here is the node module I'm trying to build:

const Path = require('paper').Path
const Point = require('paper').Point
const Project = require('paper').Project

// the next line produces side effects without which 
// the code will not run, but I'm not sure this is the way to go.
let p = new Project() 

function simplify (points) {
  let pts = []
  for (let point in points) {
    let pt = new Point(point.x, point.y)
    pts.push(pt)
  }
  let path = new Path({
    segments: pts,
    strokeColor: 'black',
    fullySelected: false
  })
  path.simplify(10)

  let simplePath = []
  for (const segment of path.segments) {
    // only one segment reaches this point
    // with all zeros in all the parameters
    console.log(segment.path)
    simplePath.push(
      {
        handleIn: { x: segment.handleIn.x, y: segment.handleIn.y },
        handleOut: { x: segment.handleOut.x, y: segment.handleOut.y },
        point: { x: segment.point.x, y: segment.point.y }
      })
    console.log(`
    hi   : (${segment.handleIn.x}, ${segment.handleIn.y})
    ho   : (${segment.handleOut.x}, ${segment.handleOut.y})
    point: (${segment.point.x}, ${segment.point.y})`)
  }
  return simplePath
}
module.exports = simplify

Answer 1

I think that your error is here:

for (let point in points) {
    let pt = new Point(point.x, point.y);
    pts.push(pt);
}

If, as I think, the variable points contains an array of objects, you should instead use:

for (let point of points) {
    let pt = new Point(point.x, point.y);
    pts.push(pt);
}

Note the keyword of replacing in in the for loop.
You are actually looping over the keys and not the values.