Get SHA-256 from asset

get_sha_from_file.js

fetch('/assets/app.bundle.js')
  .then(response => { if (response.status > 200) throw new Error('not found'); return response.arrayBuffer() })
  .then(async (buffer) => {
    const hashBuffer = await crypto.subtle.digest('SHA-256', buffer);
    const hashArray = Array.from(new Uint8Array(hashBuffer));
    return hashArray.map(b => ('00' + b.toString(16)).slice(-2)).join('');
})
  .then(console.log)