index.js

const fs = require('fs');
const asar = require('@electron/asar');

const bold = s => `\u001b[1m${s}\u001b[0m`;
const underline = s => `\u001b[4m${s}\u001b[0m`;
const color = (r, g, b, s) => `\u001b[38;2;${r};${g};${b}m${s}\u001b[0m`;
const severity = (percent, s) => color(Math.max(60, Math.floor(percent / maxPercent * 255)), 60, 60, s);

const file = process.argv[2];

console.log(bold(underline(file)));

const fileSize = fs.statSync(file).size;

let lastSize;
try {
  lastSize = parseInt(fs.readFileSync(__dirname + '/last_size.txt', 'utf8'));
} catch { }

fs.writeFileSync(__dirname + '/last_size.txt', fileSize.toString());

const { header } = asar.getRawHeader(file);

let files = {};

const goThrough = (f, x) => {
  if (x.files) {
    for (const y in x.files) {
      goThrough((f ? f + '/' : '') + y, x.files[y]);
    }

    return;
  }

  files[f] = x;
};

goThrough('', header);

for (const f in files) {
  files[f] = [ (new TextEncoder().encode(JSON.stringify(files[f]))).length, files[f].size ];
  files[f][2] = files[f][0] + files[f][1];
}
const oldFiles = { ...files };

for (const f in files) {
  const sum = files[f][0] + files[f][1];
  files[f] = (sum / fileSize) * 100;
}

const filenames = Object.keys(files).sort((a, b) => files[b] - files[a]);
const maxPercent = files[filenames[0]];

// console.log(Object.keys(files).sort((a, b) => files[b] - files[a]).reduce((acc, x) => { acc[x] = files[x].toFixed(2) + '%'; return acc; }, {}));
for (const f of filenames) {
  console.log(severity(files[f], bold(f)), ' '.repeat(30 - f.length + (files[f] < 10 ? 1 : 0)), files[f].toFixed(2) + '%', `${color(80, 80, 80, '║')} ${oldFiles[f][2] / 1024 < 10 ? ' ' : ''}${(oldFiles[f][2] / 1024).toFixed(2)} kb` + color(80, 80, 80, ` + ${(oldFiles[f][0] / 1024).toFixed(2)} kb header`));
}

console.log();
console.log('file size:', fileSize / 1024 + ' kb');
console.log('DIFF', `${((fileSize - lastSize) / 1024).toFixed(3)} kb`)