Library

The Library service manages a user’s saved content — albums and tracks.

Saved Tracks

Get saved tracks

import { Effect } from "effect";
import { Library, makeSpotifyLayer } from "@spotify-effect/core";

const program = Effect.gen(function* () {
  const library = yield* Library;

  const saved = yield* library.getSavedTracks({
    limit: 50,
    market: "US",
  });

  for (const item of saved.items) {
    console.log(`${item.track.name} — ${item.added_at}`);
  }
});

Check if tracks are saved

const program = Effect.gen(function* () {
  const library = yield* Library;

  const results = yield* library.areTracksSaved([
    "4cOdK2wGLETKBW3PvgPWqT",
    "5as3aKm2oGOikBg4arGMLi",
  ]);

  results.forEach((isSaved, i) => {
    console.log(`Track ${i}: ${isSaved ? "Saved" : "Not saved"}`);
  });
});

Save tracks

yield * library.saveTracks(["4cOdK2wGLETKBW3PvgPWqT", "5as3aKm2oGOikBg4arGMLi"]);

Remove saved tracks

yield * library.removeSavedTracks(["4cOdK2wGLETKBW3PvgPWqT"]);

Saved Albums

Get saved albums

const program = Effect.gen(function* () {
  const library = yield* Library;

  const saved = yield* library.getSavedAlbums({
    limit: 50,
  });

  for (const item of saved.items) {
    console.log(`${item.album.name} — ${item.added_at}`);
  }
});

Check if albums are saved

const results =
  yield * library.areAlbumsSaved(["4aawyAB9vmqN3uQ7FjRGTy", "6rqhFgbbKwnb9MLmUQDhG6"]);

Save albums

yield * library.saveAlbums(["4aawyAB9vmqN3uQ7FjRGTy"]);

Remove saved albums

yield * library.removeSavedAlbums(["4aawyAB9vmqN3uQ7FjRGTy"]);

Practical Examples

Save search results to library

import { Effect } from "effect";
import { Library, Search } from "@spotify-effect/core";

const saveSearchToLibrary = (query: string) =>
  Effect.gen(function* () {
    const library = yield* Library;
    const search = yield* Search;

    const results = yield* search.search(query, ["track"], { limit: 50 });
    const trackIds = results.tracks?.items.map((t) => t.id) ?? [];

    const [saved, notSaved] = yield* Effect.all([
      library.areTracksSaved(trackIds),
      Effect.succeed(trackIds),
    ]);

    const toSave = trackIds.filter((_, i) => !saved[i]);
    if (toSave.length > 0) {
      yield* library.saveTracks(toSave);
    }

    return { saved: toSave.length };
  });

Sync playlist to library

const syncPlaylistToLibrary = (playlistId: string) =>
  Effect.gen(function* () {
    const library = yield* Library;
    const playlists = yield* Playlists;
    const albums = yield* Albums;

    const tracks = yield* paginateAll(
      (offset, limit) => playlists.getPlaylistItems(playlistId, { offset, limit }),
      100,
    );

    const trackIds = tracks.items
      .map((item) => (item.track?._tag === "Track" ? item.track.id : null))
      .filter((id): id is string => id !== null);

    const albumIds = [
      ...new Set(
        tracks.items
          .map((item) => (item.track?._tag === "Track" ? item.track.album.id : null))
          .filter((id): id is string => id !== null),
      ),
    ];

    const [savedTracks, savedAlbums] = yield* Effect.all([
      library.areTracksSaved(trackIds),
      library.areAlbumsSaved(albumIds),
    ]);

    const tracksToSave = trackIds.filter((_, i) => !savedTracks[i]);
    const albumsToSave = albumIds.filter((_, i) => !savedAlbums[i]);

    if (tracksToSave.length > 0) {
      yield* library.saveTracks(tracksToSave);
    }
    if (albumsToSave.length > 0) {
      yield* library.saveAlbums(albumsToSave);
    }

    return {
      tracksSaved: tracksToSave.length,
      albumsSaved: albumsToSave.length,
    };
  });

Export library to playlist

const exportLibraryToPlaylist = (userId: string, name: string) =>
  Effect.gen(function* () {
    const library = yield* Library;
    const playlists = yield* Playlists;

    const savedTracks = yield* paginateAll(
      (offset, limit) => library.getSavedTracks({ offset, limit }),
      50,
    );

    const playlist = yield* playlists.createPlaylist(userId, name, {
      description: "My saved tracks",
      public: false,
    });

    const trackUris = savedTracks
      .map((item) => item.track?.uri)
      .filter((uri): uri is string => uri !== undefined);

    for (let i = 0; i < trackUris.length; i += 100) {
      yield* playlists.addItemsToPlaylist(playlist.id, trackUris.slice(i, i + 100));
    }

    return { playlist, trackCount: trackUris.length };
  });

Pagination

Use paginateAll for large libraries:

import { paginateAll } from "@spotify-effect/core";

const getAllSavedTracks = () =>
  Effect.gen(function* () {
    const library = yield* Library;

    return yield* paginateAll((offset, limit) => library.getSavedTracks({ offset, limit }), 50);
  });

const getAllSavedAlbums = () =>
  Effect.gen(function* () {
    const library = yield* Library;

    return yield* paginateAll((offset, limit) => library.getSavedAlbums({ offset, limit }), 50);
  });

Scopes Required

Operation	Required Scope
getSavedTracks, getSavedAlbums	user-library-read
saveTracks, saveAlbums	user-library-modify
removeSavedTracks, removeSavedAlbums	user-library-modify
areTracksSaved, areAlbumsSaved	user-library-read

Next steps

• Playlists — manage playlists
• Search — find content to save
• Tracks — get audio features