commaOperator1.js

// On renders
const renderFoo = (data) => (<div>{data.code}</div>)

// On some shit code
cosnt mapState = (state) => ({
   userName: state.users && state.users.activeUser && state.users.activeUser.name,
   customer: state.customer && state.customer.cars,
})

// Inside conditional expressions
if (currentCustomer && currentCustomer.balance < 200) {} else {}

// Some more
<span>{!isLoading && currentCustomer && currentCustomer.isVIP ? currentCustomer.balance : null}</span>;