// This function receives as arguments an array of objects,// [{ firstName: 'Test' }, { firstName: 'Ignacio' }, ...]// This function returns all the users with name 'Test' const findTestNameUsers = (users) => {  const usersFound = users.filter((user) => {    return user.firstName === 'Test'  })  return usersFound}// This function has the same behaviour as the one above.// This function uses implicit return statementsconst findTestNameUsers = (users) => (  users.filter(user => user.firstName === 'Test'))

// This function receives as arguments an array of objects,// [{ firstName: 'Test' }, { firstName: 'Ignacio' }, ...]// This function returns all the users with name 'Test' const newFunction = (a) => (  a.filter(u => u.firstName === 'Test'))// You can see, how by giving better naming to the function it // is easier to identify what they do.const findTestNameUsers = (users) => (  users.filter(user => user.firstName === 'Test'))

const greeting = trueconst welcomeGreeting = 'Welcome to the condition'const notWelcome = 'Not Welcome to the condition'const notGreeting = 'No Greeting for you'// Pretty confusing the line below...const value = greeting ? welcomeGreeting ? welcomeGreeting : notWelcome : noGreetingconsole.log(value) // will console.log Welcome to the condition.// Let me change that to make it easier to read, // we will add a couple more lines but it will make your life // easier.const greeting = trueconst welcomeGreeting = 'Welcome to the condition'const notWelcome = 'Not Welcome to the condition'const notGreeting = 'No Greeting for you'if(greeting) {  console.log(welcomeGreeting ? welcomeGreeting : notWelcome)} else {  console.log(noGreeting)}

const argument = null// For this check, you will have to make an extra operation,// ! => not, therefore, if there is NO argument, // then run the following block.if (!argument) {  return 'The argument is empty'} else {  return 'The argument is not empty'}// Let's convert the previous block to a positive checkconst argument = nullif (argument) {  return 'The argument is present'} else {  return 'The argument is not present'}

// The key is already the perfect variable name, why not use it?const userFirstName = user.firstName// Much cleaner!const { firstName } = user