From 1c8e6a8344830f60d7858903fb6dac142520661d Mon Sep 17 00:00:00 2001
From: Benjamin Schulz <beschulz@betabugs.de>
Date: Wed, 25 Feb 2015 21:16:57 +0100
Subject: [PATCH] * outputting empty son-array, if the requested channel cannot
 be generated (because there are not enough channels). This is done, so that
 client-side javascript code does not break.

---
 examples/test1.json | 5 +++++
 src/wav2json.cpp    | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/examples/test1.json b/examples/test1.json
index cee59e6..8d015e7 100644
--- a/examples/test1.json
+++ b/examples/test1.json
@@ -1,5 +1,10 @@
 {
   "_generator":"wav2json version 0.4 on Darwin (http://goo.gl/af7wg)",
+  "right":[],
+  "mid":[],
+  "side":[],
+  "min":[],
+  "max":[],
   "left": [0,0.5,0.87,1,0.87,0.5,0,0.5,0.87,0,0.87,0.5],
   "duration":0.000250
 }
diff --git a/src/wav2json.cpp b/src/wav2json.cpp
index 33c1d6f..39c9211 100644
--- a/src/wav2json.cpp
+++ b/src/wav2json.cpp
@@ -113,7 +113,7 @@ void compute_waveform(
 
   // filter out channels, that require more channels than the wav file has
   channels.erase(
-      std::remove_if(channels.begin(), channels.end(), [&wav](Options::Channel channel){
+      std::remove_if(channels.begin(), channels.end(), [&wav, &output_stream](Options::Channel channel){
           if ((channel == Options::MID  ||
                channel == Options::SIDE ||
                channel == Options::RIGHT||
@@ -122,6 +122,7 @@ void compute_waveform(
                wav.channels() == 1
           )
           {
+            output_stream << "  \"" << channel << "\":[]," << endl; // output empty array, so that existing client-code does not break
             std::cerr << "Warning: your trying to generate output for channel '" << channel << "', but the input has only one channel. removing requested channel." << std::endl;
             return true;
           }