function buildKey() from module 'ws' returns empty hashed

Try to run as may test as possible to make sure SDK 2.21 for ESP8266 can be released.

function buildKey() {
      var randomString = btoa(Math.random().toString(36).substr(2, 8)+
                          Math.random().toString(36).substr(2, 8));
      var toHash = randomString + '258EAFA5-E914-47DA-95CA-C5AB0DC85B11';
      return {
          source: randomString,
          hashed: btoa(require('crypto').SHA1(toHash))
      }
}

console.log(buildKey());
{
    "source": "MXFwZDFiamFmM2Jyd2xsaA==",
    "hashed": ""
 }

Shouldn't hashed has a non empty string?