From f0e68af8423e317511919706d2ae07b67506de8c Mon Sep 17 00:00:00 2001
From: Wender Rodrigo de Oliveira Alves <wender.rodrigo@seduc.go.gov.br>
Date: Tue, 24 Mar 2026 09:40:58 -0300
Subject: [PATCH] feat: add support for alphanumeric CNPJ

---
 src/validations/utils.ts        |  3 +-
 src/validations/validateCNPJ.ts | 65 ++++++++++++++++++++++++---------
 2 files changed, 49 insertions(+), 19 deletions(-)

diff --git a/src/validations/utils.ts b/src/validations/utils.ts
index e6e89fd..abb9d80 100644
--- a/src/validations/utils.ts
+++ b/src/validations/utils.ts
@@ -5,8 +5,7 @@
  * @returns a boolean value.
  */
 export const isRepeated = (ref: string) => {
-  const ret = ref.replace(new RegExp(ref[0], 'g'), '').trim().length === 0;
-  return ret;
+  return /^([A-Z0-9])\1+$/.test(ref);
 };
 
 /**
diff --git a/src/validations/validateCNPJ.ts b/src/validations/validateCNPJ.ts
index ac23ee8..b0031bd 100644
--- a/src/validations/validateCNPJ.ts
+++ b/src/validations/validateCNPJ.ts
@@ -1,40 +1,71 @@
 import { isRepeated } from './utils';
 
 /**
- * The function `validateCNPJ` validates a Brazilian CNPJ number.
- * @param {string} value - The `value` parameter is a string that represents the CNPJ (Cadastro
- * Nacional da Pessoa Jurídica) number to be validated. It can be formatted with or without punctuation,
- * like '00.000.000/0000-00' or '00000000000000'.
- * @returns The function `validateCNPJ` returns a boolean value. It returns `true` if the CNPJ is
- * valid, and `false` otherwise.
+ * The function `validateCNPJ` validates a Brazilian CNPJ number, supporting both
+ * the traditional numeric format and the new alphanumeric format introduced by Receita Federal.
+ *
+ * @param {string} value - The `value` parameter is a string representing the CNPJ number to be validated.
+ * It can contain formatting characters (such as '.', '/', '-') and may include letters (A-Z) in the first
+ * 12 positions, as allowed in the new alphanumeric CNPJ format.
+ *
+ * Examples of valid inputs:
+ * - '00.000.000/0000-00' (numeric format)
+ * - '00000000000000' (numeric without formatting)
+ * - 'A1.BC2.34D/56EF-90' (alphanumeric format)
+ * - 'A1BC234D56EF90' (alphanumeric without formatting)
+ *
+ * @returns {boolean} Returns `true` if the CNPJ is valid according to the official
+ * validation algorithm (modulo 11), or `false` otherwise.
+ *
+ * @description
+ * The validation process includes:
+ * - Normalizing the input by removing all non-alphanumeric characters and converting to uppercase
+ * - Verifying that the length is exactly 14 characters
+ * - Rejecting sequences with all identical characters
+ * - Converting alphanumeric characters to numeric values (A=10, B=11, ..., Z=35)
+ * - Calculating the two verification digits using the modulo 11 algorithm
+ *
+ * This function is fully compatible with both legacy numeric CNPJs and the new alphanumeric standard.
  */
 export function validateCNPJ(value: string): boolean {
-  const cnpj = String(value).replace(/[^\d]+/g, '');
+  const clean = (value || "")
+    .toUpperCase()
+    .replace(/[^A-Z0-9]/g, "");
 
-  if (cnpj === '' || cnpj.length !== 14 || isRepeated(cnpj)) {
+  if (clean.length !== 14 || isRepeated(clean)) {
     return false;
   }
 
-  const calculateDigit = (numbers: string, weights: number[]): number => {
+  // Converte caractere para número (0-9 ou A=10 ... Z=35)
+  const charToNumber = (char: string): number => {
+    if (/[0-9]/.test(char)) return parseInt(char, 10);
+    return char.charCodeAt(0) - 55; // A=10, B=11...
+  };
+
+  const calculateDigit = (base: string, weights: number[]): number => {
     let sum = 0;
-    for (let i = 0; i < numbers.length; i++) {
-      sum += parseInt(numbers.charAt(i), 10) * weights[i];
+
+    for (let i = 0; i < base.length; i++) {
+      sum += charToNumber(base[i]) * weights[i];
     }
+
     const remainder = sum % 11;
     return remainder < 2 ? 0 : 11 - remainder;
   };
 
+  const base12 = clean.substring(0, 12);
+
   const weights1 = [5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3, 2];
-  const first12 = cnpj.substring(0, 12);
-  const dv1 = calculateDigit(first12, weights1);
+  const dv1 = calculateDigit(base12, weights1);
 
-  if (dv1 !== parseInt(cnpj.charAt(12), 10)) {
+  if (dv1 !== charToNumber(clean[12])) {
     return false;
   }
 
+  const base13 = clean.substring(0, 13);
+
   const weights2 = [6, 5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3, 2];
-  const first13 = cnpj.substring(0, 13);
-  const dv2 = calculateDigit(first13, weights2);
+  const dv2 = calculateDigit(base13, weights2);
 
-  return dv2 === parseInt(cnpj.charAt(13), 10);
+  return dv2 === charToNumber(clean[13]);
 }