feat: Add a method to play beep tones

packages/blockly/core/workspace_audio.ts

@@ -83,24 +83,10 @@ export class WorkspaceAudio {
    * @param opt_volume Volume of sound (0-1).
    */
   async play(name: string, opt_volume?: number) {
-    if (this.muted || opt_volume === 0 || !this.context) {
-      return;
-    }
+    if (!this.isPlayingAllowed() || opt_volume === 0) return;
     const sound = this.sounds.get(name);
     if (sound) {
-      // Don't play one sound on top of another.
-      const now = new Date();
-      if (
-        this.lastSound !== null &&
-        now.getTime() - this.lastSound.getTime() < SOUND_LIMIT
-      ) {
-        return;
-      }
-      this.lastSound = now;
-
-      if (this.context.state === 'suspended') {
-        await this.context.resume();
-      }
+      await this.prepareToPlay();
 
       const source = this.context.createBufferSource();
       const gainNode = this.context.createGain();
@@ -121,6 +107,73 @@ export class WorkspaceAudio {
     }
   }
 
+  /**
+   * Plays a beep at the given frequency.
+   *
+   * @param tone The frequency of the beep to play, in hertz.
+   * @param duration The duration of the beep, in seconds. Defaults to 0.2.
+   */
+  async beep(tone: number, duration = 0.2) {
+    if (!this.isPlayingAllowed()) return;
+    await this.prepareToPlay();
+
+    const oscillator = this.context.createOscillator();
+    oscillator.type = 'sine';
+    oscillator.frequency.setValueAtTime(tone, this.context.currentTime);
+
+    const gainNode = this.context.createGain();
+    gainNode.gain.setValueAtTime(0, this.context.currentTime);
+    // Fade in
+    gainNode.gain.linearRampToValueAtTime(0.5, this.context.currentTime + 0.01);
+    // Fade out
+    gainNode.gain.linearRampToValueAtTime(
+      0,
+      this.context.currentTime + duration,
+    );
+
+    oscillator.connect(gainNode);
+    gainNode.connect(this.context.destination);
+
+    oscillator.start(this.context.currentTime);
+    oscillator.stop(this.context.currentTime + duration);
+  }
+
+  /**
+   * Returns whether or not playing sounds is currently allowed.
+   *
+   * @returns False if audio is muted or a sound has just been played, otherwise
+   *     true.
+   */
+  private isPlayingAllowed(
+    this: WorkspaceAudio,
+  ): this is WorkspaceAudio & Required<{context: AudioContext}> {
+    const now = new Date();
+
+    if (
+      this.getMuted() ||
+      !this.context ||
+      (this.lastSound !== null &&
+        now.getTime() - this.lastSound.getTime() < SOUND_LIMIT)
+    ) {
+      return false;
+    }
+    return true;
+  }
+
+  /**
+   * Prepares to play audio by recording the time of the last play and resuming
+   * the audio context.
+   */
+  private async prepareToPlay(
+    this: WorkspaceAudio & Required<{context: AudioContext}>,
+  ) {
+    this.lastSound = new Date();
+
+    if (this.context.state === 'suspended') {
+      await this.context.resume();
+    }
+  }
+
   /**
    * @param muted If true, mute sounds. Otherwise, play them.
    */