Get all the json files from https://jlptstudy.net/

main.js

import fs from "node:fs";
import axios from "axios";

const baseUrl = "https://jlptstudy.net";
const pattern = /<a\s+(?:[^>]*?\s+)?href=(["'])(.*?)\1/g;

(async () => {
  // stop at 1 cause jlptstudy.net doesn't have the kanji n1
  for (let nNumber = 5; nNumber > 1; nNumber--) {
    const dirname = "n" + nNumber;
    fs.mkdirSync(dirname);

    const indexUrl = baseUrl + `/N${nNumber}/lists/`;
    const response = await axios.get(indexUrl);
    const matchedHref = response.data.matchAll(pattern);

    for (const href of matchedHref) {
      const filename = href[2];

      if (filename.startsWith("n" + nNumber) && filename.endsWith("json")) {
        const response = await axios.get(indexUrl + filename);
        fs.writeFileSync(`./${dirname}/${filename}`, JSON.stringify(response.data));
      }
    }
  }
})();