const hashBrowser = val =>
  crypto.subtle.digest('SHA-256', new TextEncoder('utf-8').encode(val)).then(h => {
    let hexes = [],
      view = new DataView(h);
    for (let i = 0; i < view.byteLength; i += 4)
      hexes.push(('00000000' + view.getUint32(i).toString(16)).slice(-8));
    return hexes.join('');
  });

hashBrowser(JSON.stringify({ a: 'a', b: [1, 2, 3, 4], foo: { c: 'bar' } })).then(console.log);