RingBuffer: Default to 0 if arraySequence[0] is undefined (#542)

Co-authored-by: Robert Kayson <[email protected]>

Author: MrRoboman

src/audioWorklet/ringBuffer.js

@@ -63,7 +63,7 @@ class RingBuffer {
     // match with this buffer obejct.
 
     // Transfer data from the |arraySequence| storage to the internal buffer.
-    let sourceLength = arraySequence[0].length;
+    let sourceLength = arraySequence[0] ? arraySequence[0].length : 0;
     for (let i = 0; i < sourceLength; ++i) {
       let writeIndex = (this._writeIndex + i) % this._length;
       for (let channel = 0; channel < this._channelCount; ++channel) {