diff --git a/nr-common/mod.ts b/nr-common/mod.ts
index f9bc066..8118f09 100644
--- a/nr-common/mod.ts
+++ b/nr-common/mod.ts
@@ -1,5 +1,6 @@
 import { OPEN_LOCATION_CODE_TAG_NAME } from "./constants.ts";
 import { z } from "./deps.ts";
+import { isPlusCode } from "./utils.ts";
 
 // import { version as PACKAGE_VERSION } from "./deno.json" with { type: "json" };
 export const CONTENT_MINIMUM_LENGTH = 3;
@@ -7,16 +8,6 @@ export const CONTENT_MAXIMUM_LENGTH = 300;
 
 const PACKAGE_VERSION = "0.0.1";
 
-function isHex(s: string) {
-  return s.split("").every((c) => "0123456789abcdef".split("").includes(c));
-}
-
-function isPlusCode(code: string) {
-  const re =
-    /(^|\s)([23456789C][23456789CFGHJMPQRV][23456789CFGHJMPQRVWX]{6}\+[23456789CFGHJMPQRVWX]{2,7})(\s|$)/i;
-  return re.test(code);
-}
-
 export const eventSchema = z
   .object({
     id: z.string().length(64),
diff --git a/nr-common/utils.ts b/nr-common/utils.ts
index 0f1e12e..ff635ac 100644
--- a/nr-common/utils.ts
+++ b/nr-common/utils.ts
@@ -24,6 +24,12 @@ export function isHexKey(key: string): boolean {
   return true;
 }
 
+export function isPlusCode(code: string) {
+  const re =
+    /(^|\s)([23456789C][23456789CFGHJMPQRV][23456789CFGHJMPQRVWX]{6}\+[23456789CFGHJMPQRVWX]{2,7})(\s|$)/i;
+  return re.test(code);
+}
+
 export function getCurrentTimestamp() {
   return Math.round(Date.now() / 1e3);
 }
@@ -84,8 +90,11 @@ export function getAllPlusCodePrefixes(
   plusCode: string,
   minimumLength: number
 ): string[] {
+  if (minimumLength % 2 !== 0) {
+    throw new Error("#HqXbxX-invalid-minimum-length");
+  }
   const numberOfCodes = (8 - minimumLength) / 2 + 1;
-  const plusCodes = Array.from({ length: numberOfCodes }).map((_value, index) =>
+  const plusCodes = Array.from({ length: numberOfCodes }, (_value, index) =>
     getPlusCodePrefix(plusCode, minimumLength + index * 2)
   );
   return plusCodes;