make-assets-hash.js

const outputJs = process.argv[2];
const outputScss = process.argv[3];

if (outputJs === undefined) {
  console.log('Missing js output path');
  process.exit(1);
} else if (outputScss === undefined) {
  console.log('Missing scss output path');
  process.exit(1);
}

const fs = require('fs');
const path = require('path');
const crypto = require('crypto');

const assetsBasePath = 'assets';

function pair (fst, snd) {
  return { fst: fst, snd: snd };
}

function md5 (str) {
  return crypto
    .createHash('md5')
    .update(str)
    .digest('hex');
}

function recHash (file, hashs = []) {
  if (fs.statSync(file).isDirectory()) {
    const files = fs.readdirSync(file);

    files.forEach(p => recHash(path.join(file, p), hashs));
  } else {
    const content = fs.readFileSync(file);

    hashs.push(pair(file, md5(content)));
  }

  return hashs;
}

const allAssetsHashes = recHash(assetsBasePath)
  .filter(a => !a.fst.endsWith('.scss'))
  .filter(a => !a.fst.endsWith('.js'))
  .sort((a, b) => a.fst > b.fst)
  .map(a => a.snd)
  .reduce((acc, hash) => acc + hash);

const assetsHash = md5(allAssetsHashes);

const options = { mode: 0o644, encoding: 'utf8' };

let output = '';

output = 'var assetsHash = "' + assetsHash + '";\n';
fs.writeFileSync(outputJs, output, options);
console.log('Successfully generated', outputJs);

output = '$assets-hash: "' + assetsHash + '";\n';
fs.writeFileSync(outputScss, output, options);
console.log('Successfully generated', outputScss);