Fetch all tracks from a playlist

import { Client, PlaylistTrack } from '[email protected]';

import * as wmill from 'windmill-client';

type Spotify = {

  token: string;

}

const MAX_TRACKS_PER_PAGE = 100; // this is the max limit allowed by the API

export async function main(

  spotifyCredentials: Spotify,

  playlistId: string,

  fetchIntervalMs: number = 1000,

  failOnSizeMismatch: boolean = false

) {

  const client = await Client.create({

    token: spotifyCredentials.token,

    userAuthorizedToken: true

  });

  const playlist = await client.playlists.get(playlistId);

  if (!playlist) {

    throw new Error(`getPlaylist call returned null (id: ${playlistId})`);

  }

  console.log(`Fetching all ${playlist.totalTracks} tracks from playlist '${playlist.name}' (id: ${playlistId})`);

  const results: PlaylistTrack[] = [];

  while (results.length < playlist.totalTracks) {

      if (results.length != 0) {

        // wait for a specified interval between calls to avoid being rate limited

        await new Promise(res => setTimeout(res, fetchIntervalMs));

      }

      const tracks = await client.playlists.getTracks(playlistId, {

        offset: results.length,

        limit: MAX_TRACKS_PER_PAGE

      });

      if (tracks.length === 0) {

        break;

      }

      results.push(...tracks);

      const percentProgress = (results.length / playlist.totalTracks) * 100;

      await wmill.setProgress(percentProgress);

      console.log(`Fetched ${tracks.length} tracks (${results.length} total, ${percentProgress.toFixed(2)}% done)`);

  }

  if (playlist.totalTracks !== results.length) {

    const errorMessage = `The input playlist contains ${playlist.totalTracks} tracks but the result contains ${results.length} tracks. The size of the playlist may have changed during this script's execution`;

    if (failOnSizeMismatch) {

      throw new Error(errorMessage);

    }

    console.error(`WARNING: ${errorMessage}`);

  }

  console.log(`Returning ${results.length} total fetched tracks`);

  return results;

}