let jiro = { name : "jiro" , age : 28 }; for( const key in jiro ){ console.log(key + '：' + jiro[key]); } let members = { jiro11tanaka: { name: 'jiro', age: 28 }, yuko0yoshida: { name: 'yuko', age: 22 }, hiyoko: { name: 'hiyoko', age: 18 }, 24568: { name: 'even', age: 28 }, 16729: { name: 'prime', age: 28 } } for( const key in members ){ console.log(key); console.log(members[key]); }