text: const fs = require("fs");
  const path = require("path");
  const unzip = require("unzip-stream");
  const readline = require("readline");
  
  const dataset = [];
  
  module.exports = () =>
    new Promise((resolve, reject) => {
      if (dataset.length > 0) {
        resolve(dataset);
      } else {
        const file = path.resolve(`COTAHIST_A${process.env.YEAR}.ZIP`);
  
        fs.createReadStream(file)
          .pipe(unzip.Parse())
          .on("entry", function (entry) {
            const rl = readline.createInterface({
              input: entry,
              crlfDelay: Infinity,
            });
            rl.on("line", (line) => {
              dataset.push(line);
            });
  
            rl.on("close", () => resolve(dataset));
          });
      }
    });
  