fix(browser): stop creating throwaway AudioContext in getSampleRate

src/browser/speakers.js

@@ -91,13 +91,10 @@ export default class Speakers {
   }
 
   getSampleRate() {
-    if (!window.AudioContext) {
-      return 44100;
+    if (this.audioCtx) {
+      return this.audioCtx.sampleRate;
     }
-    let myCtx = new window.AudioContext();
-    let sampleRate = myCtx.sampleRate;
-    myCtx.close();
-    return sampleRate;
+    return 44100;
   }
 
   // start() is async because audioWorklet.addModule() returns a promise.

test/speakers.spec.js

@@ -0,0 +1,29 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import Speakers from "../src/browser/speakers.js";
+
+test("getSampleRate returns default without creating AudioContext", () => {
+  let constructions = 0;
+  globalThis.window = {
+    AudioContext: class {
+      constructor() {
+        constructions++;
+        this.sampleRate = 48000;
+      }
+    },
+  };
+
+  const speakers = new Speakers({ onBufferUnderrun: () => {} });
+
+  assert.equal(speakers.getSampleRate(), 44100);
+  assert.equal(constructions, 0);
+});
+
+test("getSampleRate uses active audio context sample rate", () => {
+  globalThis.window = {};
+  const speakers = new Speakers({ onBufferUnderrun: () => {} });
+  speakers.audioCtx = { sampleRate: 48000 };
+
+  assert.equal(speakers.getSampleRate(), 48000);
+});