refactor api client to use string method

hoping to use this for requestKey/deduping next

app/state/library.ts

@@ -20,10 +20,9 @@ import {
   GetSongResponse,
   GetTopSongsResponse,
   Search3Response,
-  SubsonicResponse,
 } from '@app/subsonic/responses'
 import PromiseQueue from '@app/util/PromiseQueue'
-import { reduceById, mergeById } from '@app/util/state'
+import { mergeById, reduceById } from '@app/util/state'
 import { WritableDraft } from 'immer/dist/types/types-external'
 import pick from 'lodash.pick'
 
@@ -99,9 +98,9 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
       return
     }
 
-    let response: SubsonicResponse<GetArtistsResponse>
+    let response: GetArtistsResponse
     try {
-      response = await client.getArtists()
+      response = await client.fetch('getArtists')
     } catch {
       return
     }
@@ -121,9 +120,9 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
       return
     }
 
-    let response: SubsonicResponse<GetArtistResponse>
+    let response: GetArtistResponse
     try {
-      response = await client.getArtist({ id })
+      response = await client.fetch('getArtist', { id })
     } catch {
       return
     }
@@ -145,9 +144,9 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
       return
     }
 
-    let response: SubsonicResponse<GetArtistInfo2Response>
+    let response: GetArtistInfo2Response
     try {
-      response = await client.getArtistInfo2({ id })
+      response = await client.fetch('getArtistInfo2', { id })
     } catch {
       return
     }
@@ -165,9 +164,9 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
       return
     }
 
-    let response: SubsonicResponse<GetTopSongsResponse>
+    let response: GetTopSongsResponse
     try {
-      response = await client.getTopSongs({ artist: artistName, count: 50 })
+      response = await client.fetch('getTopSongs', { artist: artistName, count: 50 })
     } catch {
       return
     }
@@ -189,9 +188,9 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
       return
     }
 
-    let response: SubsonicResponse<GetAlbumResponse>
+    let response: GetAlbumResponse
     try {
-      response = await client.getAlbum({ id })
+      response = await client.fetch('getAlbum', { id })
     } catch {
       return
     }
@@ -215,9 +214,9 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
       return
     }
 
-    let response: SubsonicResponse<GetPlaylistsResponse>
+    let response: GetPlaylistsResponse
     try {
-      response = await client.getPlaylists()
+      response = await client.fetch('getPlaylists', {})
     } catch {
       return
     }
@@ -237,9 +236,9 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
       return
     }
 
-    let response: SubsonicResponse<GetPlaylistResponse>
+    let response: GetPlaylistResponse
     try {
-      response = await client.getPlaylist({ id })
+      response = await client.fetch('getPlaylist', { id })
     } catch {
       return
     }
@@ -263,9 +262,9 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
       return
     }
 
-    let response: SubsonicResponse<GetSongResponse>
+    let response: GetSongResponse
     try {
-      response = await client.getSong({ id })
+      response = await client.fetch('getSong', { id })
     } catch {
       return
     }
@@ -285,9 +284,9 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
       return []
     }
 
-    let response: SubsonicResponse<GetAlbumList2Response>
+    let response: GetAlbumList2Response
     try {
-      response = await client.getAlbumList2(params)
+      response = await client.fetch('getAlbumList2', params)
     } catch {
       return []
     }
@@ -308,9 +307,9 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
       return empty
     }
 
-    let response: SubsonicResponse<Search3Response>
+    let response: Search3Response
     try {
-      response = await client.search3(params)
+      response = await client.fetch('search3', params)
     } catch {
       return empty
     }
@@ -366,7 +365,7 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
     })
 
     try {
-      await client.star(params)
+      await client.fetch('star', params)
     } catch {
       set(state => {
         if (originalValue !== null) {
@@ -405,7 +404,7 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
     })
 
     try {
-      await client.unstar(params)
+      await client.fetch('unstar', params)
     } catch {
       set(state => {
         if (originalValue !== null) {
@@ -441,7 +440,7 @@ export const createLibrarySlice = (set: SetStore, get: GetStore): LibrarySlice =
 
     for (const id in albumsToGet) {
       songCoverArtQueue
-        .enqueue(() => client.getAlbum({ id }))
+        .enqueue(() => client.fetch('getAlbum', { id }))
         .then(res => {
           const album = mapAlbum(res.data.album)
 

app/state/settings.ts

@@ -220,7 +220,7 @@ export const createSettingsSlice = (set: SetStore, get: GetStore): SettingsSlice
     }
 
     try {
-      await client.ping()
+      await client.fetch('ping')
       return true
     } catch {
       return false

app/state/trackplayer.ts

@@ -298,7 +298,7 @@ export const createTrackPlayerSlice = (set: SetStore, get: GetStore): TrackPlaye
     }
 
     try {
-      await client.scrobble({ id })
+      await client.fetch('scrobble', { id })
     } catch {}
   },
 

app/subsonic/api.ts

@@ -32,6 +32,7 @@ import {
   GetPlaylistsResponse,
   GetSongResponse,
   GetTopSongsResponse,
+  NullResponse,
   Search3Response,
   SubsonicResponse,
 } from '@app/subsonic/responses'
@@ -54,6 +55,48 @@ export class SubsonicApiError extends Error {
   }
 }
 
+type ResponseType<T extends SubsonicResponse> = (xml: Document) => T
+
+type RequestParams = {
+  getIndexes: GetIndexesParams
+  getMusicDirectory: GetMusicDirectoryParams
+  getAlbum: GetAlbumParams
+  getArtistInfo: GetArtistInfoParams
+  getArtistInfo2: GetArtistInfo2Params
+  getArtist: GetArtistParams
+  getTopSongs: GetTopSongsParams
+  getSong: GetSongParams
+  getAlbumList: GetAlbumListParams
+  getAlbumList2: GetAlbumList2Params
+  getPlaylists: GetPlaylistsParams
+  getPlaylist: GetPlaylistParams
+  scrobble: ScrobbleParams
+  star: StarParams
+  unstar: StarParams
+  search3: Search3Params
+}
+
+const Methods = {
+  ping: (xml => new NullResponse(xml)) as ResponseType<NullResponse>,
+  getArtists: (xml => new GetArtistsResponse(xml)) as ResponseType<GetArtistsResponse>,
+  getIndexes: (xml => new GetIndexesResponse(xml)) as ResponseType<GetIndexesResponse>,
+  getMusicDirectory: (xml => new GetMusicDirectoryResponse(xml)) as ResponseType<GetMusicDirectoryResponse>,
+  getAlbum: (xml => new GetAlbumResponse(xml)) as ResponseType<GetAlbumResponse>,
+  getArtistInfo: (xml => new GetArtistInfoResponse(xml)) as ResponseType<GetArtistInfoResponse>,
+  getArtistInfo2: (xml => new GetArtistInfo2Response(xml)) as ResponseType<GetArtistInfo2Response>,
+  getArtist: (xml => new GetArtistResponse(xml)) as ResponseType<GetArtistResponse>,
+  getTopSongs: (xml => new GetTopSongsResponse(xml)) as ResponseType<GetTopSongsResponse>,
+  getSong: (xml => new GetSongResponse(xml)) as ResponseType<GetSongResponse>,
+  getAlbumList: (xml => new GetAlbumListResponse(xml)) as ResponseType<GetAlbumListResponse>,
+  getAlbumList2: (xml => new GetAlbumList2Response(xml)) as ResponseType<GetAlbumList2Response>,
+  getPlaylists: (xml => new GetPlaylistsResponse(xml)) as ResponseType<GetPlaylistsResponse>,
+  getPlaylist: (xml => new GetPlaylistResponse(xml)) as ResponseType<GetPlaylistResponse>,
+  scrobble: (xml => new NullResponse(xml)) as ResponseType<NullResponse>,
+  star: (xml => new NullResponse(xml)) as ResponseType<NullResponse>,
+  unstar: (xml => new NullResponse(xml)) as ResponseType<NullResponse>,
+  search3: (xml => new Search3Response(xml)) as ResponseType<Search3Response>,
+}
+
 export class SubsonicApiClient {
   address: string
   username: string
@@ -129,96 +172,14 @@ export class SubsonicApiClient {
     return params
   }
 
-  //
-  // System
-  //
-
-  async ping(): Promise<SubsonicResponse<null>> {
-    const xml = await this.apiGetXml('ping')
-    return new SubsonicResponse<null>(xml, null)
+  async fetch<T extends keyof typeof Methods>(
+    method: T,
+    ...params: T extends Extract<keyof RequestParams, T> ? [RequestParams[Extract<keyof RequestParams, T>]] : []
+  ): Promise<ReturnType<typeof Methods[T]>> {
+    const xml = await this.apiGetXml(method, params.length > 0 ? params[0] : undefined)
+    return Methods[method](xml) as ReturnType<typeof Methods[T]>
   }
 
-  //
-  // Browsing
-  //
-
-  async getArtists(): Promise<SubsonicResponse<GetArtistsResponse>> {
-    const xml = await this.apiGetXml('getArtists')
-    return new SubsonicResponse<GetArtistsResponse>(xml, new GetArtistsResponse(xml))
-  }
-
-  async getIndexes(params?: GetIndexesParams): Promise<SubsonicResponse<GetIndexesResponse>> {
-    const xml = await this.apiGetXml('getIndexes', params)
-    return new SubsonicResponse<GetIndexesResponse>(xml, new GetIndexesResponse(xml))
-  }
-
-  async getMusicDirectory(params: GetMusicDirectoryParams): Promise<SubsonicResponse<GetMusicDirectoryResponse>> {
-    const xml = await this.apiGetXml('getMusicDirectory', params)
-    return new SubsonicResponse<GetMusicDirectoryResponse>(xml, new GetMusicDirectoryResponse(xml))
-  }
-
-  async getAlbum(params: GetAlbumParams): Promise<SubsonicResponse<GetAlbumResponse>> {
-    const xml = await this.apiGetXml('getAlbum', params)
-    return new SubsonicResponse<GetAlbumResponse>(xml, new GetAlbumResponse(xml))
-  }
-
-  async getArtistInfo(params: GetArtistInfoParams): Promise<SubsonicResponse<GetArtistInfoResponse>> {
-    const xml = await this.apiGetXml('getArtistInfo', params)
-    return new SubsonicResponse<GetArtistInfoResponse>(xml, new GetArtistInfoResponse(xml))
-  }
-
-  async getArtistInfo2(params: GetArtistInfo2Params): Promise<SubsonicResponse<GetArtistInfo2Response>> {
-    const xml = await this.apiGetXml('getArtistInfo2', params)
-    return new SubsonicResponse<GetArtistInfo2Response>(xml, new GetArtistInfo2Response(xml))
-  }
-
-  async getArtist(params: GetArtistParams): Promise<SubsonicResponse<GetArtistResponse>> {
-    const xml = await this.apiGetXml('getArtist', params)
-    return new SubsonicResponse<GetArtistResponse>(xml, new GetArtistResponse(xml))
-  }
-
-  async getTopSongs(params: GetTopSongsParams): Promise<SubsonicResponse<GetTopSongsResponse>> {
-    const xml = await this.apiGetXml('getTopSongs', params)
-    return new SubsonicResponse<GetTopSongsResponse>(xml, new GetTopSongsResponse(xml))
-  }
-
-  async getSong(params: GetSongParams): Promise<SubsonicResponse<GetSongResponse>> {
-    const xml = await this.apiGetXml('getSong', params)
-    return new SubsonicResponse<GetSongResponse>(xml, new GetSongResponse(xml))
-  }
-
-  //
-  // Album/song lists
-  //
-
-  async getAlbumList(params: GetAlbumListParams): Promise<SubsonicResponse<GetAlbumListResponse>> {
-    const xml = await this.apiGetXml('getAlbumList', params)
-    return new SubsonicResponse<GetAlbumListResponse>(xml, new GetAlbumListResponse(xml))
-  }
-
-  async getAlbumList2(params: GetAlbumList2Params): Promise<SubsonicResponse<GetAlbumList2Response>> {
-    const xml = await this.apiGetXml('getAlbumList2', params)
-    return new SubsonicResponse<GetAlbumList2Response>(xml, new GetAlbumList2Response(xml))
-  }
-
-  //
-  // Playlists
-  //
-
-  async getPlaylists(params?: GetPlaylistsParams): Promise<SubsonicResponse<GetPlaylistsResponse>> {
-    const xml = await this.apiGetXml('getPlaylists', params)
-    return new SubsonicResponse<GetPlaylistsResponse>(xml, new GetPlaylistsResponse(xml))
-  }
-
-  async getPlaylist(params: GetPlaylistParams): Promise<SubsonicResponse<GetPlaylistResponse>> {
-    const xml = await this.apiGetXml('getPlaylist', params)
-    return new SubsonicResponse<GetPlaylistResponse>(xml, new GetPlaylistResponse(xml))
-  }
-
-  //
-  // Media retrieval
-  //
-
   getCoverArtUri(params?: GetCoverArtParams): string {
     return this.buildUrl('getCoverArt', params)
   }
@@ -226,32 +187,4 @@ export class SubsonicApiClient {
   streamUri(params: StreamParams): string {
     return this.buildUrl('stream', params)
   }
-
-  //
-  // Media annotation
-  //
-
-  async scrobble(params: ScrobbleParams): Promise<SubsonicResponse<undefined>> {
-    const xml = await this.apiGetXml('scrobble', params)
-    return new SubsonicResponse<undefined>(xml, undefined)
-  }
-
-  async star(params: StarParams): Promise<SubsonicResponse<undefined>> {
-    const xml = await this.apiGetXml('star', params)
-    return new SubsonicResponse<undefined>(xml, undefined)
-  }
-
-  async unstar(params: StarParams): Promise<SubsonicResponse<undefined>> {
-    const xml = await this.apiGetXml('unstar', params)
-    return new SubsonicResponse<undefined>(xml, undefined)
-  }
-
-  //
-  // Searching
-  //
-
-  async search3(params: Search3Params): Promise<SubsonicResponse<Search3Response>> {
-    const xml = await this.apiGetXml('search3', params)
-    return new SubsonicResponse<Search3Response>(xml, new Search3Response(xml))
-  }
 }

app/subsonic/responses.ts

@@ -12,128 +12,161 @@ import {
 
 export type ResponseStatus = 'ok' | 'failed'
 
-export class SubsonicResponse<T> {
+export class SubsonicResponse {
   status: ResponseStatus
   version: string
-  data: T
 
-  constructor(xml: Document, data: T) {
-    this.data = data
+  constructor(xml: Document) {
     this.status = xml.documentElement.getAttribute('status') as ResponseStatus
     this.version = xml.documentElement.getAttribute('version') as string
   }
 }
 
+export class NullResponse extends SubsonicResponse {
+  data = null
+}
+
 //
 // Browsing
 //
 
-export class GetArtistsResponse {
-  ignoredArticles: string
-  artists: ArtistID3Element[] = []
+export class GetArtistsResponse extends SubsonicResponse {
+  data: {
+    ignoredArticles: string
+    artists: ArtistID3Element[]
+  }
 
   constructor(xml: Document) {
-    this.ignoredArticles = xml.getElementsByTagName('artists')[0].getAttribute('ignoredArticles') as string
+    super(xml)
 
-    const artistElements = xml.getElementsByTagName('artist')
-    for (let i = 0; i < artistElements.length; i++) {
-      this.artists.push(new ArtistID3Element(artistElements[i]))
+    this.data = {
+      ignoredArticles: xml.getElementsByTagName('artists')[0].getAttribute('ignoredArticles') || '',
+      artists: Array.from(xml.getElementsByTagName('artist')).map(i => new ArtistID3Element(i)),
     }
   }
 }
 
-export class GetArtistResponse {
-  artist: ArtistID3Element
-  albums: AlbumID3Element[] = []
+export class GetArtistResponse extends SubsonicResponse {
+  data: {
+    artist: ArtistID3Element
+    albums: AlbumID3Element[]
+  }
 
   constructor(xml: Document) {
-    this.artist = new ArtistID3Element(xml.getElementsByTagName('artist')[0])
+    super(xml)
 
-    const albumElements = xml.getElementsByTagName('album')
-    for (let i = 0; i < albumElements.length; i++) {
-      this.albums.push(new AlbumID3Element(albumElements[i]))
+    this.data = {
+      artist: new ArtistID3Element(xml.getElementsByTagName('artist')[0]),
+      albums: Array.from(xml.getElementsByTagName('album')).map(i => new AlbumID3Element(i)),
     }
   }
 }
 
-export class GetIndexesResponse {
-  ignoredArticles: string
-  lastModified: number
-  artists: ArtistElement[] = []
+export class GetIndexesResponse extends SubsonicResponse {
+  data: {
+    ignoredArticles: string
+    lastModified: number
+    artists: ArtistElement[]
+  }
 
   constructor(xml: Document) {
+    super(xml)
+
     const indexesElement = xml.getElementsByTagName('indexes')[0]
 
-    this.ignoredArticles = indexesElement.getAttribute('ignoredArticles') as string
-    this.lastModified = parseInt(indexesElement.getAttribute('lastModified') as string, 10)
-
-    const artistElements = xml.getElementsByTagName('artist')
-    for (let i = 0; i < artistElements.length; i++) {
-      this.artists.push(new ArtistElement(artistElements[i]))
+    this.data = {
+      ignoredArticles: indexesElement.getAttribute('ignoredArticles') || '',
+      lastModified: parseInt(indexesElement.getAttribute('lastModified') || '0', 10),
+      artists: Array.from(xml.getElementsByTagName('artist')).map(i => new ArtistElement(i)),
     }
   }
 }
 
-export class GetArtistInfoResponse {
-  artistInfo: ArtistInfoElement
-
-  constructor(xml: Document) {
-    this.artistInfo = new ArtistInfoElement(xml.getElementsByTagName('artistInfo')[0])
+export class GetArtistInfoResponse extends SubsonicResponse {
+  data: {
+    artistInfo: ArtistInfoElement
   }
-}
-
-export class GetArtistInfo2Response {
-  artistInfo: ArtistInfo2Element
 
   constructor(xml: Document) {
-    this.artistInfo = new ArtistInfo2Element(xml.getElementsByTagName('artistInfo2')[0])
-  }
-}
+    super(xml)
 
-export class GetMusicDirectoryResponse {
-  directory: DirectoryElement
-  children: ChildElement[] = []
-
-  constructor(xml: Document) {
-    this.directory = new DirectoryElement(xml.getElementsByTagName('directory')[0])
-
-    const childElements = xml.getElementsByTagName('child')
-    for (let i = 0; i < childElements.length; i++) {
-      this.children.push(new ChildElement(childElements[i]))
+    this.data = {
+      artistInfo: new ArtistInfoElement(xml.getElementsByTagName('artistInfo')[0]),
     }
   }
 }
 
-export class GetAlbumResponse {
-  album: AlbumID3Element
-  songs: ChildElement[] = []
+export class GetArtistInfo2Response extends SubsonicResponse {
+  data: {
+    artistInfo: ArtistInfo2Element
+  }
 
   constructor(xml: Document) {
-    this.album = new AlbumID3Element(xml.getElementsByTagName('album')[0])
+    super(xml)
 
-    const childElements = xml.getElementsByTagName('song')
-    for (let i = 0; i < childElements.length; i++) {
-      this.songs.push(new ChildElement(childElements[i]))
+    this.data = {
+      artistInfo: new ArtistInfo2Element(xml.getElementsByTagName('artistInfo2')[0]),
     }
   }
 }
 
-export class GetTopSongsResponse {
-  songs: ChildElement[] = []
+export class GetMusicDirectoryResponse extends SubsonicResponse {
+  data: {
+    directory: DirectoryElement
+    children: ChildElement[]
+  }
 
   constructor(xml: Document) {
-    const childElements = xml.getElementsByTagName('song')
-    for (let i = 0; i < childElements.length; i++) {
-      this.songs.push(new ChildElement(childElements[i]))
+    super(xml)
+
+    this.data = {
+      directory: new DirectoryElement(xml.getElementsByTagName('directory')[0]),
+      children: Array.from(xml.getElementsByTagName('child')).map(i => new ChildElement(i)),
     }
   }
 }
 
-export class GetSongResponse {
-  song: ChildElement
+export class GetAlbumResponse extends SubsonicResponse {
+  data: {
+    album: AlbumID3Element
+    songs: ChildElement[]
+  }
 
   constructor(xml: Document) {
-    this.song = new ChildElement(xml.getElementsByTagName('song')[0])
+    super(xml)
+
+    this.data = {
+      album: new AlbumID3Element(xml.getElementsByTagName('album')[0]),
+      songs: Array.from(xml.getElementsByTagName('song')).map(i => new ChildElement(i)),
+    }
+  }
+}
+
+export class GetTopSongsResponse extends SubsonicResponse {
+  data: {
+    songs: ChildElement[]
+  }
+
+  constructor(xml: Document) {
+    super(xml)
+
+    this.data = {
+      songs: Array.from(xml.getElementsByTagName('song')).map(i => new ChildElement(i)),
+    }
+  }
+}
+
+export class GetSongResponse extends SubsonicResponse {
+  data: {
+    song: ChildElement
+  }
+
+  constructor(xml: Document) {
+    super(xml)
+
+    this.data = {
+      song: new ChildElement(xml.getElementsByTagName('song')[0]),
+    }
   }
 }
 
@@ -141,13 +174,16 @@ export class GetSongResponse {
 // Album/song lists
 //
 
-class BaseGetAlbumListResponse<T> {
-  albums: T[] = []
+class BaseGetAlbumListResponse<T> extends SubsonicResponse {
+  data: {
+    albums: T[]
+  }
 
-  constructor(xml: Document, albumType: new (e: Element) => T) {
-    const albumElements = xml.getElementsByTagName('album')
-    for (let i = 0; i < albumElements.length; i++) {
-      this.albums.push(new albumType(albumElements[i]))
+  constructor(xml: Document, AlbumType: new (e: Element) => T) {
+    super(xml)
+
+    this.data = {
+      albums: Array.from(xml.getElementsByTagName('album')).map(i => new AlbumType(i)),
     }
   }
 }
@@ -168,22 +204,31 @@ export class GetAlbumList2Response extends BaseGetAlbumListResponse<AlbumID3Elem
 // Playlists
 //
 
-export class GetPlaylistsResponse {
-  playlists: PlaylistElement[] = []
+export class GetPlaylistsResponse extends SubsonicResponse {
+  data: {
+    playlists: PlaylistElement[]
+  }
 
   constructor(xml: Document) {
-    const playlistElements = xml.getElementsByTagName('playlist')
-    for (let i = 0; i < playlistElements.length; i++) {
-      this.playlists.push(new PlaylistElement(playlistElements[i]))
+    super(xml)
+
+    this.data = {
+      playlists: Array.from(xml.getElementsByTagName('playlist')).map(i => new PlaylistElement(i)),
     }
   }
 }
 
-export class GetPlaylistResponse {
-  playlist: PlaylistWithSongsElement
+export class GetPlaylistResponse extends SubsonicResponse {
+  data: {
+    playlist: PlaylistWithSongsElement
+  }
 
   constructor(xml: Document) {
-    this.playlist = new PlaylistWithSongsElement(xml.getElementsByTagName('playlist')[0])
+    super(xml)
+
+    this.data = {
+      playlist: new PlaylistWithSongsElement(xml.getElementsByTagName('playlist')[0]),
+    }
   }
 }
 
@@ -191,25 +236,20 @@ export class GetPlaylistResponse {
 // Searching
 //
 
-export class Search3Response {
-  artists: ArtistID3Element[] = []
-  albums: AlbumID3Element[] = []
-  songs: ChildElement[] = []
+export class Search3Response extends SubsonicResponse {
+  data: {
+    artists: ArtistID3Element[]
+    albums: AlbumID3Element[]
+    songs: ChildElement[]
+  }
 
   constructor(xml: Document) {
-    const artistElements = xml.getElementsByTagName('artist')
-    for (let i = 0; i < artistElements.length; i++) {
-      this.artists.push(new ArtistID3Element(artistElements[i]))
-    }
+    super(xml)
 
-    const albumElements = xml.getElementsByTagName('album')
-    for (let i = 0; i < albumElements.length; i++) {
-      this.albums.push(new AlbumID3Element(albumElements[i]))
-    }
-
-    const songElements = xml.getElementsByTagName('song')
-    for (let i = 0; i < songElements.length; i++) {
-      this.songs.push(new ChildElement(songElements[i]))
+    this.data = {
+      artists: Array.from(xml.getElementsByTagName('artist')).map(i => new ArtistID3Element(i)),
+      albums: Array.from(xml.getElementsByTagName('album')).map(i => new AlbumID3Element(i)),
+      songs: Array.from(xml.getElementsByTagName('song')).map(i => new ChildElement(i)),
     }
   }
 }