Follow

The Follow service manages relationships with artists, users, and playlists.

Following Artists

Follow artists

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

const program = Effect.gen(function* () {
  const follow = yield* Follow;

  yield* follow.followArtists(["0YC192cP3KPCRWx8zr8MfZ", "2YZyLoL8N0Wb9xBt1NhZWg"]);
});

Unfollow artists

yield * follow.unfollowArtists(["0YC192cP3KPCRWx8zr8MfZ"]);

Check if following artists

const program = Effect.gen(function* () {
  const follow = yield* Follow;

  const results = yield* follow.isFollowingArtists([
    "0YC192cP3KPCRWx8zr8MfZ",
    "2YZyLoL8N0Wb9xBt1NhZWg",
  ]);

  results.forEach((isFollowing, i) => {
    console.log(`Artist ${i}: ${isFollowing ? "Following" : "Not following"}`);
  });
});

Following Users

Follow users

yield * follow.followUsers(["user123", "user456"]);

Unfollow users

yield * follow.unfollowUsers(["user123"]);

Check if following users

const results = yield * follow.isFollowingUsers(["user123", "user456"]);

Following Playlists

Follow a playlist

const program = Effect.gen(function* () {
  const follow = yield* Follow;

  yield* follow.followPlaylist("37i9dQZF1DXcBWIGoYBM5M", {
    public: true, // Make public
  });
});

Unfollow a playlist

yield * follow.unfollowPlaylist("37i9dQZF1DXcBWIGoYBM5M");

Check if following a playlist

const program = Effect.gen(function* () {
  const follow = yield* Follow;

  const results = yield* follow.areFollowingPlaylist("37i9dQZF1DXcBWIGoYBM5M", [
    "user123",
    "user456",
  ]);

  results.forEach((isFollowing, i) => {
    console.log(`User ${i}: ${isFollowing ? "Following" : "Not following"}`);
  });
});

Getting Followed Artists

Get followed artists

const program = Effect.gen(function* () {
  const follow = yield* Follow;

  const artists = yield* follow.getFollowedArtists({
    limit: 50,
    after: "0YC192cP3KPCRWx8zr8MfZ", // Cursor for pagination
  });

  for (const artist of artists.items) {
    console.log(`${artist.name} (${artist.followers.total} followers)`);
  }
});

Get all followed artists

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

const getAllFollowedArtists = () =>
  Effect.gen(function* () {
    const follow = yield* Follow;

    return yield* cursorPaginateAll((options) => follow.getFollowedArtists(options), 50);
  });

Practical Examples

Sync followed artists to a playlist

import { Effect } from "effect";
import { Follow, Artists, Playlists, Users, cursorPaginateAll } from "@spotify-effect/core";

const syncFollowedArtists = (playlistName: string) =>
  Effect.gen(function* () {
    const follow = yield* Follow;
    const artists = yield* Artists;
    const playlists = yield* Playlists;
    const users = yield* Users;

    const me = yield* users.getCurrentUserProfile();

    const followedArtists = yield* cursorPaginateAll(
      (options) => follow.getFollowedArtists(options),
      50,
    );

    const artistIds = followedArtists.map((a) => a.id);
    const topTracks = yield* Effect.all(
      artistIds.map((id) => artists.getArtistTopTracks(id, "US")),
      { concurrency: 5 },
    );

    const tracks = topTracks.flatMap((t) => t.slice(0, 2));
    const trackUris = tracks.map((t) => t.uri);

    const playlist = yield* playlists.createPlaylist(me.id, playlistName, {
      description: "Your followed artists top tracks",
      public: false,
    });

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

    return playlist;
  });

Find mutual followers

const getMutualFollowers = (targetUserId: string) =>
  Effect.gen(function* () {
    const follow = yield* Follow;
    const users = yield* Users;

    const me = yield* users.getCurrentUserProfile();
    const target = yield* users.getUser(targetUserId);

    return {
      mutual: `Check ${target.display_name}'s followers for ${me.id}`,
    };
  });

Scopes Required

Operation	Required Scope
getFollowedArtists	user-follow-read
followArtists / unfollowArtists	user-follow-modify
followUsers / unfollowUsers	user-follow-modify
followPlaylist	playlist-modify-public or playlist-modify-private
unfollowPlaylist	playlist-modify-public or playlist-modify-private
isFollowingArtists	user-follow-read
isFollowingUsers	user-follow-read
areFollowingPlaylist	playlist-read-private

Next steps

• Personalization — user’s top artists/tracks
• Playlists — manage playlists
• Users — user profiles