From 149b2ab9f9420549db48b6d7b7140f1019a12538 Mon Sep 17 00:00:00 2001
From: Felix Roos <roos@entrecode.de>
Date: Thu, 15 Sep 2022 20:11:10 +0200
Subject: [PATCH] make vowel work with node

---
 packages/webaudio/vowel.mjs | 53 +++++++++++++++++++------------------
 1 file changed, 27 insertions(+), 26 deletions(-)

diff --git a/packages/webaudio/vowel.mjs b/packages/webaudio/vowel.mjs
index c35b1ebd..25357642 100644
--- a/packages/webaudio/vowel.mjs
+++ b/packages/webaudio/vowel.mjs
@@ -6,32 +6,33 @@ export var vowelFormant = {
   o: { freqs: [430, 820, 2700, 3000, 3300], gains: [1, 0.3162, 0.0501, 0.0794, 0.01995], qs: [40, 80, 100, 120, 120] },
   u: { freqs: [370, 630, 2750, 3000, 3400], gains: [1, 0.1, 0.0708, 0.0316, 0.01995], qs: [40, 60, 100, 120, 120] },
 };
-
-class VowelNode extends GainNode {
-  constructor(ac, letter) {
-    super(ac);
-    if (!vowelFormant[letter]) {
-      throw new Error('vowel: unknown vowel ' + letter);
+if (typeof GainNode !== 'undefined') {
+  class VowelNode extends GainNode {
+    constructor(ac, letter) {
+      super(ac);
+      if (!vowelFormant[letter]) {
+        throw new Error('vowel: unknown vowel ' + letter);
+      }
+      const { gains, qs, freqs } = vowelFormant[letter];
+      const makeupGain = ac.createGain();
+      for (let i = 0; i < 5; i++) {
+        const gain = ac.createGain();
+        gain.gain.value = gains[i];
+        const filter = ac.createBiquadFilter();
+        filter.type = 'bandpass';
+        filter.Q.value = qs[i];
+        filter.frequency.value = freqs[i];
+        this.connect(filter);
+        filter.connect(gain);
+        gain.connect(makeupGain);
+      }
+      makeupGain.gain.value = 8; // how much makeup gain to add?
+      this.connect = (target) => makeupGain.connect(target);
+      return this;
     }
-    const { gains, qs, freqs } = vowelFormant[letter];
-    const makeupGain = ac.createGain();
-    for (let i = 0; i < 5; i++) {
-      const gain = ac.createGain();
-      gain.gain.value = gains[i];
-      const filter = ac.createBiquadFilter();
-      filter.type = 'bandpass';
-      filter.Q.value = qs[i];
-      filter.frequency.value = freqs[i];
-      this.connect(filter);
-      filter.connect(gain);
-      gain.connect(makeupGain);
-    }
-    makeupGain.gain.value = 8; // how much makeup gain to add?
-    this.connect = (target) => makeupGain.connect(target);
-    return this;
   }
-}
 
-AudioContext.prototype.createVowelFilter = function (letter) {
-  return new VowelNode(this, letter);
-};
+  AudioContext.prototype.createVowelFilter = function (letter) {
+    return new VowelNode(this, letter);
+  };
+}