What does this JavaScript code print?

printNullness(JSON.parse('{ "lemmings": [] }'));
printNullness(JSON.parse('{ "lemmings": null }'));
printNullness(JSON.parse('{ "lemmings": "null" }'));
function printNullness(testMe) {
  if (testMe.lemmings == null) console.log('null');
  else console.log('not null');
}