// npm install martinez-polygon-clipping polygon-clipping
// node index.js

const fs = require('fs');

const martinez = require('martinez-polygon-clipping');
const polygonClipping = require('polygon-clipping');

const input = require('./input.json');
const clip = require('./clip.json');

function apply(op, area, clip) {
  // console.log(input);
  // console.log(clip);
  const result = op(
    area,
    clip,
  );
  return JSON.stringify({
    'type': 'FeatureCollection',
    'features': [{
      'type': 'Feature',
      'properties': {},
      'geometry': {
        'type': 'MultiPolygon',
        'coordinates': result
      }
    }]
  });
}

fs.writeFileSync('./expected.json', apply(
  polygonClipping.difference,
  input.features[0].geometry.coordinates,
  clip.features[0].geometry.coordinates
));
fs.writeFileSync('./actual.json', apply(
  martinez.diff,
  input.features[0].geometry.coordinates,
  clip.features[0].geometry.coordinates
));