I'm really struggling with how to be able to search via both Song and Artist name. Each are in their own collections and are connected via an ID. I have written the aggregate successfully, however the search term only filters via the Song name. Is there a way I can make this search by both song name and artist name. The second field I want to search by is the artistName on the project object. As an example of the new search that doesn't work - "Bust A Move Young MC", with "Young MC being" the artist name. In the current state, this simply returns 0 results. Any help would be much appreciated.

      const searchTerm = 'Bust A Move'
  let filter = []

  const s = new RegExp(searchTerm.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, '\\$&'), 'gi')
  filter = ['name'].map((field) => ({
    [field]: s
  }))

  const agg = await Song.aggregate([
    {
      $lookup: {
        from: 'artists',
        localField: 'artist_id',
        foreignField: 'artist_id',
        as: 'artist'
      }
    },
    { $unwind: '$artist' },
    {
      $match: {
        $or: filter
      }
    },
    {
      $project: {
        _id: 1,
        name: 1,
        song_id: 1,
        spotifyImg640: 1,
        artist_id: '$artist.artist_id',
        artistName: {
          name: '$artist.name'
        }
      }
    }
  ])

// Song Object
{
song_id: 1
name: "Bust A Move",
artist_id: 1
}

// Artist Object
{
artist_id: 1,
name: "Young MC"
}