igeligel

const basePerson = {
  firstName: "Max"
};

const person = {
  ...basePerson,
  lastName: ""
};

igeligel

const basePerson = {
  firstName: "Max"
};
const person = Object.assign({}, basePerson, { lastName: "" });

igeligel

const condition = true;
const result = condition && { lastName: "" };
console.log(result);
// Will log { lastName: "" }

igeligel

const a = false;
const b = true;
const result = a && b;
console.log(result);
// Will log false

const c = false;
const d = false;
const result = c && d;
console.log(result);

igeligel

const a = true;
const b = true;
const result = a && b;
console.log(result);
// Will log true

igeligel

const a = true;
const b = "Magic String";
const result = a && b;
console.log(result);
// Will log "Magic String"

igeligel

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

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

igeligel

const person = {
  firstName: "Max"
};

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

if (condition) {
  person.lastName = "";
}

igeligel

const person = {
  firstName: "Max"
};

const condition = getCondition();

if (condition) {
  person.lastName = "";
}

igeligel

const person = {
  firstName: "Max"
};
person.lastName = "";