javascript conditionally add to object code example

Example 1: js conditional object property

const a = {
   ...(someCondition && {b: 5})
}

Example 2: conditionally add key to object javascript

const condition = getCondition();
const additionalCondition = getAdditionalCondition();

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