小编Mar*_*ONE的帖子

MessageThread.findById(req.body._id)
      .populate({ path: "messages" })
      .exec((err, foundMessageThread) => {
        var filtered = foundMessageThread.messages.map(message=>{
          return Object.assign({}, message, {isRead: true});
        })
        console.log("filtered", filtered);

      });

console.log显示:

{ '$__':
 InternalCache {
   strictMode: true,
   selected: {},
   shardval: undefined,
   saveError: undefined,
   validationError: undefined,
   adhocPaths: undefined,
   removing: undefined,
   inserting: undefined,
   version: undefined,
   getters: {},
   _id: 5a4c7f2d8b49fc260c396f55,
   populate: undefined,
   populated: undefined,
   wasPopulated: true,
   scope: undefined,
   activePaths: [Object],
   pathsToScopes: {},
   ownerDocument: undefined,
   fullPath: undefined,
   emitter: [Object],
   '$options': true },
isNew: false,
errors: undefined,
_doc:
 { sentAt: 2018-01-03T06:58:53.188Z,
   isRead: false, …