需求：根据Id取出数组中指定的对象
let arr = [
{ id: 1, rotationAngle: 330, target: '目标1' },
{ id: 2, rotationAngle: 270, target: '目标2' },
{ id: 3, rotationAngle: 210, target: '目标三' },
]
function getTargetObjById (id) {
return arr.find(item => item.id === id)
}
console.log(getTargetObjById(2))
// { id: 2, rotationAngle: 270, target: '目标2' },
