JavaScript比较和逻辑运算符 条件运算符

逻辑运算符

&& and

|| or

! not

三元运算符(条件?true:false)

function getFee(isMember) {
  return isMember ? '$2.00' : '$10.00';
}

console.log(getFee(true));
// Expected output: "$2.00"

console.log(getFee(false));
// Expected output: "$10.00"

console.log(getFee(null));
// Expected output: "$10.00"