json-operations.js

const fs = require("fs");

/**
 * The structure contains only the song's metadata. It is used to improve
 * the loading experience by reducing size.
 */
class MetaSong {
  constructor(name, slug, author) {
    this.name = name;
    this.slug = slug;
    this.author = author;
  }
}

/**
 * The function generates the JSON file, which contains only the song's
 * metadata without page content to reduce the loading performance
 * of the index page.
 */
function generateMetaJson() {
  console.log(
    "~~~~~\nThe function for generating JSON file with song's metadata has been started!"
  );

  const files = fs.readdirSync("_songs");
  let out = new Array();
  files.map((file) => {
    const song = JSON.parse(fs.readFileSync(`_songs/${file}`));
    out.push(new MetaSong(song.name, song.slug, song.author));
  });
  fs.writeFileSync("_songs-metadata.json", JSON.stringify(out));
  console.log(
    "The function for generating JSON file with song's metadata succesful end!\n~~~~~"
  );
}

function printManual() {
  console.log(`
    MANUAL FOR JSON OPERATIONS
    -m  run the function generates the JSON file, which contains only the song's
        metadata without page content to reduce the loading performance
        of the index page
    -h  print manual
  `);
}

if (process.argv[2] === "-m") {
  generateMetaJson();
  process.exit(0);
} else if (process.argv[2] === "-h") {
  printManual();
  process.exit(0);
} else {
  printManual();
  process.exit(1);
}