请问js这样的数组如何合并

Question

{   con:[      {content:"dsa",evaId:29,id:38,types:1},      {content:"dfsd",evaId:30,id:39,types:1},      {content:"dsf",evaId:33,id:42,types:1},      {content:"sd213",evaId:37,id:47,types:1}   ],   body:[      {content:"dsa",id:30,types:1},      {content:"dfsd",id:39,types:1},      {content:"dsf",id:33,types:1},      {content:"sd213",id:37,types:1},      {content:"sd213",id:29,types:1}   ],   img:[      {content:"dsa",evaId:30,id:21,types:1},      {content:"dfsd",evaId:29,id:15,types:1},      {content:"dsf",evaId:33,id:12,types:1},   ]}请问怎么通过body的id合并其他两个数组的evaId来合并成一个数组？