parseCountries.js

const fs = require("fs");
const path = require("path");
const argv = process.argv;
const file = fs.readFileSync(argv[argv.length - 1], "utf8");
const geojson = JSON.parse(file);

const countriesA3 = {};
const regions = {
  all: {},
};

geojson.features.forEach((feature) => {
  // Some files have uppercase property names. This will not do.
  const lowercaseProperties = {};
  Object.keys(feature.properties).forEach((propName) => {
    lowercaseProperties[propName.toLowerCase()] = feature.properties[propName];
  });
  feature.properties = lowercaseProperties;

  // Pick out the country name and put it in a file.
  const regionName = feature.properties.continent;
  regions[regionName] = regions[regionName] || {};

  const countryName = feature.properties.name;

  let a3 = feature.properties.iso_a3;
  if (!a3 || Number(a3) === -99) {
    if (["Country", "Sovereign country"].includes(feature.properties.type)) {
      a3 = feature.properties.gu_a3;
    } else {
      a3 = feature.properties.name.toLowerCase().replace(/\W/g, "");
    }
  }
  console.log(
    "country",
    countryName,
    feature.properties.iso_a3,
    JSON.stringify(a3)
  );

  if (countriesA3[a3]) {
    console.error(a3, countryName, "already exists");
    console.log(JSON.stringify(feature.properties));
  }
  countriesA3[a3] = a3;

  const filename = a3 + ".geojson";
  feature.properties.filename = filename;

  regions[regionName][countryName] = filename;
  regions.all[a3] = { filename, countryName };
  fs.writeFileSync(path.join(process.cwd(), filename), JSON.stringify(feature));
});

fs.writeFileSync(
  path.join(process.cwd(), "index.json"),
  JSON.stringify(regions)
);