From f20bae83f3423a0397874822fcd1847ab6f0b5e5 Mon Sep 17 00:00:00 2001
From: Pat Sier <patrick.sier@cms.hhs.gov>
Date: Tue, 21 May 2024 10:54:23 -0400
Subject: [PATCH] fix: resolve csv column off by one error

---
 src/versions/common/csv.ts | 2 +-
 test/common/csv.spec.ts    | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)
 create mode 100644 test/common/csv.spec.ts

diff --git a/src/versions/common/csv.ts b/src/versions/common/csv.ts
index 44fbc5c..f9c14c6 100644
--- a/src/versions/common/csv.ts
+++ b/src/versions/common/csv.ts
@@ -47,7 +47,7 @@ export function csvColumnName(column: number): string {
   if (column < ASCII_UPPERCASE.length) return ASCII_UPPERCASE[column]
 
   return (
-    ASCII_UPPERCASE[Math.floor(column / ASCII_UPPERCASE.length)] +
+    ASCII_UPPERCASE[Math.floor(column / ASCII_UPPERCASE.length) - 1] +
     csvColumnName(column % ASCII_UPPERCASE.length)
   )
 }
diff --git a/test/common/csv.spec.ts b/test/common/csv.spec.ts
new file mode 100644
index 0000000..9f52b3c
--- /dev/null
+++ b/test/common/csv.spec.ts
@@ -0,0 +1,7 @@
+import test from "ava"
+import { csvColumnName } from "../../src/versions/common/csv.js"
+
+test("csvColumnName", (t) => {
+  t.is(csvColumnName(0), "A")
+  t.is(csvColumnName(26), "AA")
+})