convert.js

const fs = require('fs');
const readline = require('readline');

const removeDoubleQuotes = (value) => value.replaceAll('"', '');

const txtToJson = async (filename, columnNameMapping, jsonFilePath) => {
  const txtFilePath = `./${filename}.txt`;
  jsonFilePath = jsonFilePath || `./${filename}.json`;
  const entries = [];
  const mappingEntries = Object.entries(columnNameMapping);

  const rl = readline.createInterface({
    input: fs.createReadStream(txtFilePath),
    crlfDelay: Infinity,
  });

  for await (const line of rl) {
    if (line === '') continue;
    const lineValues = line.split('\t');
    const entry = {};
    for (const [idx, key] of mappingEntries) {
      const value = lineValues[+idx];
      if (value !== undefined) {
        entry[key] = removeDoubleQuotes(value);
      }
    }
    entries.push(entry);
  }

  console.log(`Writing ${entries.length} entries to ${jsonFilePath}`);
  await fs.promises.writeFile(
    jsonFilePath,
    JSON.stringify(entries) + '\n'
  );
};

// geonameid         : integer id of record in geonames database
// name              : name of geographical point (utf8) varchar(200)
// asciiname         : name of geographical point in plain ascii characters, varchar(200)
// alternatenames    : alternatenames, comma separated, ascii names automatically transliterated, convenience attribute from alternatename table, varchar(10000)
// latitude          : latitude in decimal degrees (wgs84)
// longitude         : longitude in decimal degrees (wgs84)
// feature class     : see http://www.geonames.org/export/codes.html, char(1)
// feature code      : see http://www.geonames.org/export/codes.html, varchar(10)
// country code      : ISO-3166 2-letter country code, 2 characters
// cc2               : alternate country codes, comma separated, ISO-3166 2-letter country code, 200 characters
// admin1 code       : fipscode (subject to change to iso code), see exceptions below, see file admin1Codes.txt for display names of this code; varchar(20)
// admin2 code       : code for the second administrative division, a county in the US, see file admin2Codes.txt; varchar(80)
// admin3 code       : code for third level administrative division, varchar(20)
// admin4 code       : code for fourth level administrative division, varchar(20)
// population        : bigint (8 byte int)
// elevation         : in meters, integer
// dem               : digital elevation model, srtm3 or gtopo30, average elevation of 3''x3'' (ca 90mx90m) or 30''x30'' (ca 900mx900m) area in meters, integer. srtm processed by cgiar/ciat.
// timezone          : the iana timezone id (see file timeZone.txt) varchar(40)
// modification date : date of last modification in yyyy-MM-dd format

(async () => {
  await Promise.all([
    txtToJson(
      'cities1000',
      {
        1: 'name',
        4: 'lat',
        5: 'lng',
        8: 'country',
        10: 'admin1',
        11: 'admin2',
      },
      './cities.json'
    ),
    txtToJson('admin1CodesASCII', { 0: 'code', 1: 'name' }, './admin1.json'),
    txtToJson('admin2Codes', { 0: 'code', 1: 'name' }, './admin2.json'),
  ]);
  console.log('All conversions complete.');
})().catch((err) => {
  console.error(err);
  process.exit(1);
});