how to skip queryselectorall does not exist or null

for (i = 0; i < document.querySelectorAll('span.movie-cast-title').length; i++)
{
  if (document.querySelectorAll('span.gcharacter')[i].innerText, == 'null') {
    continue;
  }
  data.actor.push({
    "@type": "PerformanceRole",
    "actor": {
      "@type": "Person",
      "name": document.querySelectorAll('span.movie-cast-title')[i].innerText,
      "url": document.querySelectorAll('a.movie-cast-url')[i].href,
    }
    "characterName": document.querySelectorAll('span.gcharacter')[i].innerText,
  });
}

how to skip queryselectorall does not exist or null
“characterName”: document.querySelectorAll(‘span.gcharacter’)[i].innerText