const zerocho = { 
  name: '조현영', 
  year: 1994,
  month: 8,
  date: 12, 
  gender: 'M',
};
zerocho.name;
< '조현영'
zerocho['name'];
< '조현영'
zerocho.date;
< 12 
zerocho['date'];
< 12