Async in a foreach Loop

I need to return value when every async method in a foreach has been ended.

How can I do that?

 return backupModel.find({}).exec().then(backups => {
        backupBuild = []
        backups.forEach((backup, i) => {
            userDB.getC(backup.id).then((user) =>{
                backupBuild[i]=user
            })
        })
        return backupBuild,
    });