csvTojson.js

const fs = require('fs');
const d3 = require('d3');
const path = require('path');
global.fetch = require('node-fetch');

const extension = 'js';
const csvFolder = './csv/';
const jsonFolder = './json/';
const argv = process.argv[2];
const csvFiles = isCSVfile(argv) ? [argv] : fs.readdirSync(csvFolder).filter(isCSVfile);

csvFiles.map(writeJson);

function writeJson(csvName) {
  const file = path.resolve(__dirname, `${csvFolder}${csvName}`);
  const csvdata = fs.readFileSync(file, 'utf8');
  const jsondata = d3.csvParse(csvdata);

  const targetName = `${csvName.slice(0, -4)}.${extension}`;
  const targetPath = path.resolve(__dirname, `${jsonFolder}${targetName}`);

  //es6 export
  const jsondataStr = 'export default ' + JSON.stringify(jsondata, undefined, '\t');
  fs.writeFileSync(targetPath, jsondataStr);
  /*eslint no-console: ['error', { allow: ['log', 'warn', 'error'] }] */
  console.log(targetName + ' generated!');
}

function isCSVfile(f) {
  return f && f.slice(-4) === '.csv' ? true : false;
}