feat(VoiceState): add methods for fetching voice state

#10442 backport

src/managers/VoiceStateManager.js

@@ -32,6 +32,28 @@ class VoiceStateManager extends CachedManager {
     if (cache) this.cache.set(data.user_id, entry);
     return entry;
   }
+
+  /**
+   * Obtains a user's voice state from discord or from the cache if it's already available.
+   * @param {GuildMemberResolvable|'@me'} member The member whose voice state is to be fetched
+   * @param {BaseFetchOptions} [options] Additional options for this fetch
+   * @returns {Promise<VoiceState>}
+   * @example
+   * // Fetch a member's voice state
+   * guild.voiceStates.fetch("66564597481480192")
+   *    .then(console.log)
+   *    .catch(console.error);
+   */
+  async fetch(member, { cache = true, force = false } = {}) {
+    if (!this.guild?.id) throw new Error('Guild is not defined');
+    const id = member === '@me' ? member : this.guild.members.resolveId(member);
+    if (!force) {
+      const existing = this.cache.get(id === '@me' ? this.client.user.id : id);
+      if (existing) return existing;
+    }
+    const data = await this.client.api.guilds(this.guild.id)['voice-states'][id].get();
+    return this._add(data, cache);
+  }
 }
 
 module.exports = VoiceStateManager;

src/structures/VoiceState.js

@@ -328,6 +328,15 @@ class VoiceState extends Base {
     });
   }
 
+  /**
+   * Fetches this voice state.
+   * @param {boolean} [force=true] Whether to skip the cache check and request the API
+   * @returns {Promise<VoiceState>}
+   */
+  fetch(force = true) {
+    return this.guild?.voiceStates?.fetch(this.id, { force });
+  }
+
   toJSON() {
     return super.toJSON({
       id: true,

typings/index.d.ts

@@ -3559,6 +3559,7 @@ export class VoiceState extends Base {
   public setStatus(status?: string): Promise<void>;
   public getPreview(): Promise<string>;
   public postPreview(base64Image: string): Promise<void>;
+  public fetch(force?: boolean): Promise<VoiceState>;
 }
 
 export class Webhook extends WebhookMixin() {
@@ -4579,6 +4580,7 @@ export class UserManager extends CachedManager<Snowflake, User, UserResolvable>
 export class VoiceStateManager extends CachedManager<Snowflake, VoiceState, typeof VoiceState> {
   private constructor(guild: Guild, iterable?: Iterable<RawVoiceStateData>);
   public guild: Guild;
+  public fetch(member: GuildMemberResolvable | '@me', options?: BaseFetchOptions): Promise<VoiceState>;
 }
 
 //#endregion