conditionally add key to object javascript

const a = {
   ...(someCondition && {b: 5})
}
const object = {
  ...bool && { foo: 2 },
}const condition = getCondition();
const additionalCondition = getAdditionalCondition();

const person = {
  firstName: "Max",
  ...(condition && { lastName: "" }),
  ...(additionalCondition && { addition: "" }),
};