Prisma, update scalarList/array

Question

I´m doing an Spotify clone and I´m trying to add a song to a playlist but my query doesn't work, until this point, everything was good following the documentation on prisma docs, but I cannot do this query, every time get an error, so if someone can tell me, how can I do this with an example, I'll be very grateful.

My question is, having this schema, how can I add a song to a playlist? there are two models affected by the query, song (where i am trying to add) and playlist.

My schema:

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
  shadowDatabaseUrl = env("SHADOW_DATABASE_URL")
}

model User {
  id        Int       @id @default(autoincrement())
  createdAt DateTime  @default(now())
  updatedAt DateTime  @updatedAt
  email     String    @unique
  firstName String
  lastName  String
  password  String
  playlists Playlist[]
}

// here
model Song {
  id        Int       @id @default(autoincrement())
  createdAt DateTime  @default(now())
  updatedAt DateTime  @updatedAt
  name      String
  artist    Artist    @relation(fields: [artistId], references: [id])
  artistId  Int
  playlists Playlist[]
  duration  Int
  url       String
}

model Artist {
  id        Int       @id @default(autoincrement())
  createdAt DateTime  @default(now())
  updatedAt DateTime  @updatedAt
  songs     Song[]
  name      String    @unique
}

// here
model Playlist {
  id        Int       @id @default(autoincrement())
  createdAt DateTime  @default(now())
  updatedAt DateTime  @updatedAt
  name      String
  songs     Song[]
  user      User      @relation(fields: [userId], references: [id])
  userId    Int
}

I am trying to add the song like this:

let songId = 1;
let playlistId = 1;
let lists;

// get the playlists the song is part of

lists = await prisma.song.findFirst({
        select: {
            playlists: true
        },
        where: {
            id: +songId
        }
    })

// get the playlist data i need
const list = await prisma.playlist.findUnique({
       where: {
            id: playlistId
         }
       })

// create the array for update with the data
// plus the data I want to add

lists = [ ...lists.playlists, list ]

// trying to update the old array with the new data (lists)
// this is what i'm doing wrong, help please

await prisma.song.update({
     where: { id: +songId },
     data:{
         playlists: lists

        }
     })

Answer 1

after many tries i finally got what i want if anyone knows a better way please tell me, i want to learn, for now this is my solution:

i need to send each value as id: playlistId

const song = await prisma.song.findUnique({
    select: {
       playlists: true
     },
     where: {
        id: +songId
     }
})

//   get an array of objects, id: playlistId
const songPlaylistsIds = song.playlists.map( playlist => ({id: playlist.id}))

//   I prepare the array with the content that already exists plus the new content that I want to add:
const playlists =  [...songPlaylistsIds, { id: playlistId}]

await prisma.song.update({
       where: { id: +songId },
       data:{
          playlists: {
             // finally for each object in the array i get, id: playlistId and it works.
             set: playlists.map( playlistSong => ({ ...playlistSong })) 
          }                
       }
})

Problems I had doing this: I was wrong in thinking that it should work as simple as playlist: lists I wanted to change the content to a new one but I couldn't, I needed to send the values ??one by one. Another error when I get the content of the playlists. I had the full object but just needed to send the id. And lastly, in the prisma documentation, there is a method like set, push, but this method doesn't work, at least I don't know how to make push work