JavaScript 객체에서 Null 또는 정의되지 않은 속성을 효율적으로 제거하는 방법은 무엇입니까?

// Return a new object without blank attributes
let o = Object.fromEntries(Object.entries(obj).filter(([_, v]) => v != null));

// Mutate the object in place (not recommended)
Object.keys(obj).forEach((k) => obj[k] == null && delete obj[k]);

// Return a new object with blanks removed
let o = Object.keys(obj)
  .filter((k) => obj[k] != null)
  .reduce((a, k) => ({ ...a, [k]: obj[k] }), {});

// Mutate the object in place (not recommended)
Object.keys(obj)
  .filter((k) => obj[k] != null)
  .forEach((k) => delete obj[k]);

function removeEmpty(obj) {
  const newObj = {};
  for (let prop in obj) {
    if (obj.hasOwnProperty(prop) && obj[prop] != null) {
      newObj[prop] = obj[prop];
    }
  }
  return newObj;
}