js - 取数组中每个item的某个/某些属性形成一个新的数组

1.某个属性

const arr = [ {id: 1, name: 'aaa'}, {id: 2, name: 'bbb'}, {id: 3, name: 'ccc'} ]
const res = arr.map(item => item.id)

2.某些属性

const arr = [ {id: 1, name: 'aaa', age: 18 }, {id: 2, name: 'bbb', age: 19 },
{id: 3, name: 'ccc', age: 20 } ]
const res = arr.map(item => { return {id: item.id, name: item.name} } )