const makeCat = (name, age) => {

const newCat = {

name,

age,

meow() {

return 'Meow!';

}

};

return newCat;

};

const addProperty = (object, property) => {

object[property] = null;

return object;

};

const invokeMethod = (object, method) => {

object[method]();

};

const multiplyMysteryNumberByFive = (mysteryNumberObject) => {

return mysteryNumberObject.mysteryNumber * 5;

};

const deleteProperty = (object, property) => {

delete object[property];

return object;

};

const newUser = (name, email, password) => {

const object = {

name,

email,

password

};

return object;

};

const hasEmail = (user) => {

if (user.email) {

return true;

}

return false;

};

const hasProperty = (object, property) => {

if (object[property]) {

return true;

}

return false;

};

const verifyPassword = (user, password) => {

if (user.password === password) {

return true;

}

return false;

};

const updatePassword = (user, newPassword) => {

user.password = newPassword;

return user;

};

const addFriend = (user, newFriend) => {

user.friends.push(newFriend);

return user;

};

const setUsersToPremium = (users) => {

for (let i = 0; i < users.length; i++) {

users[i].isPremium = true;

}

return users;

};

const sumUserPostLikes = (user) => {

let sumOfLikes = 0;

for (let i = 0; i < user.posts.length; i++) {

sumOfLikes += user.posts[i].likes;

}

return sumOfLikes;

};

const addCalculateDiscountPriceMethod = (storeItem) => {

storeItem.calculateDiscountPrice = () => {

const discount = storeItem.price * storeItem.discountPercentage;

return storeItem.price - discount;

};

return storeItem;

};

module.exports = {

makeCat,

addProperty,

invokeMethod,

multiplyMysteryNumberByFive,

deleteProperty,

newUser,

hasEmail,

hasProperty,

verifyPassword,

updatePassword,

addFriend,

setUsersToPremium,

sumUserPostLikes,

addCalculateDiscountPriceMethod

};