scale: throw when we can't calculate scale.

1 files changed, 2 insertions, 2 deletions

diff --git a/scale.mjs b/scale.mjs
index 5341413..485d0c5 100644
--- a/scale.mjs
+++ b/scale.mjs
@@ -18,11 +18,11 @@ function notesBetween(a, b) {
     }
 }
 
+// todo: handle tonics with a flat ‘♭’, so we can deal with [BE]♭.
 function scaleFromIntervals(tonic, intervals) {
     const scaleIndex = chromaticScale.indexOf(tonic);
     if (scaleIndex < 0) {
-        console.error('tonic not found in scale', tonic, chromaticScale);
-        return undefined;
+        throw new Error(`tonic ${tonic} not found in scale ${chromaticScale.toString()}`);
     }
 
     let scale = [tonic];