如何获取键值对的对象，其中值仅具有 mongoDB 中的投影字段

在MongoDB中，如何只将必需的字段投影到MongoDB中的嵌入对象中，其中键将是来自同一文档的选定字段的值，并根据类似的字段值对它们进行分组 如果您看到下面预期的结果，相同的car_id必须分组，值必须是ObjectId的键-值对，只有我想要的选定字段，即accessories. 让我们假设我想要使用具有honda的brand进行匹配 下面是我Collection 的名为CARS的文档

{
_id : '1'
car_id : 'A'
brand : 'honda'
accessories : [{parts:6, name:'speaker'},{parts:2, name:'headlight'}] 
},
{
_id : '2'
car_id : 'A'
brand : 'honda'
accessories : [{parts:6, name:'speaker'},{parts:2, name:'headlight'}] 
},
{
_id : '3'
car_id : 'B'
brand : 'honda'
accessories : [{parts:6, name:'speaker'},{parts:2, name:'headlight'}] 
}
{
_id : '4'
car_id : 'C'
brand : 'honda'
accessories : [{parts:6, name:'speaker'},{parts:2, name:'headlight'}] 
}

以下是我所期待的结果

{
 'A' : {
          '1': {accessories : [{parts:6, name:'speaker'},{parts:2, name:'headlight'}]}
          '2': {accessories : [{parts:6, name:'speaker'},{parts:2, name:'headlight'}]}
       },

'B' : {
          '3': {accessories : [{parts:6, name:'speaker'},{parts:2, name:'headlight'}]}
       },
'C' : {
          '4': {accessories : [{parts:6, name:'speaker'},{parts:2, name:'headlight'}]}
       },
}