为什么fullName不在空格后显示名称

const fullName = "John Doe";
const parts = fullName.split(" ");
const lastName = parts[parts.length - 1];
console.log(lastName); // 输出 "Doe"

const fullName = "John\tDoe";
const cleanedFullName = fullName.replace(/[\s\t\n\r]+/g, " ");
const parts = cleanedFullName.split(" ");
const lastName = parts[parts.length - 1];
console.log(lastName); // 输出 "Doe"

function getLastName(fullName) {
  const parts = fullName.split(" ");
  return parts[parts.length - 1];
}

const fullName = "John Doe";
const lastName = getLastName(fullName);
console.log(lastName); // 输出 "Doe"