cleanGeojson.js

const fs = require('fs');
const _get = JSON.parse(fs.readFileSync('./china.geojson'));
const geo = _get.coordinates[0]
  // console.log(geo)

const cache = new Set();
let newC = [];
geo.forEach(v => {
  let name = `${v[0]},${v[1]}`;
  if (cache.has(name)) {
    // count++;
    console.log(name);
  } else {
    newC.push(v);
    cache.add(name, v);
  }
})

_get.coordinates[0] = newC;
fs.writeFileSync('./china_after.geojson', JSON.stringify(_get));
// cache.forEach((k, v) => {
//   console.log(v)
// })
// console.log(count)