Fix: Add support for Base64 strings without padding (Issue #2501)

README.md

@@ -93,7 +93,7 @@ Validator                               | Description
 **isAscii(str)**                        | check if the string contains ASCII chars only.
 **isBase32(str [, options])**           | check if the string is base32 encoded. `options` is optional and defaults to `{ crockford: false }`.<br/> When `crockford` is true it tests the given base32 encoded string using [Crockford's base32 alternative][Crockford Base32].
 **isBase58(str)**                       | check if the string is base58 encoded.
-**isBase64(str [, options])**          | check if the string is base64 encoded. `options` is optional and defaults to `{ urlSafe: false }`<br/> when `urlSafe` is true it tests the given base64 encoded string is [url safe][Base64 URL Safe].
+**isBase64(str [, options])**          | check if the string is base64 encoded. `options` is optional and defaults to `{ urlSafe: false, ignorePadding: false }`<br/> when `urlSafe` is true it tests the given base64 encoded string is [url safe][Base64 URL Safe]. When `ignorePadding` is true it tests the given base64 encoded string without validating padding for legacy support.
 **isBefore(str [, date])**              | check if the string is a date that is before the specified date.
 **isBIC(str)**                          | check if the string is a BIC (Bank Identification Code) or SWIFT code.
 **isBoolean(str [, options])**          | check if the string is a boolean.<br/>`options` is an object which defaults to `{ loose: false }`. If `loose` is set to false, the validator will strictly match ['true', 'false', '0', '1']. If `loose` is set to true, the validator will also match 'yes', 'no', and will match a valid boolean string of any case. (e.g.: ['true', 'True', 'TRUE']).

src/lib/isBase64.js

@@ -17,6 +17,13 @@ export default function isBase64(str, options) {
     return urlSafeBase64.test(str);
   }
 
+  if (options.ignorePadding) {
+    if (str.endsWith('==')) {
+      return !notBase64.test(str) && len % 4 === 0;
+    }
+    return !notBase64.test(str);
+  }
+
   if (len % 4 !== 0 || notBase64.test(str)) {
     return false;
   }

test/validators.test.js

@@ -7202,6 +7202,37 @@ describe('Validators', () => {
       ],
     });
 
+    test({
+      validator: 'isBase64',
+      args: [{ ignorePadding: true }],
+      valid: [
+        '',
+        'dGVzdA==',
+        'dGVzdA',
+        '/u/6+w==',
+        '/u/6+w',
+        'PDw/Pz8+Pg==',
+        'PDw/Pz8+Pg',
+      ],
+      invalid: [
+        ' AA',
+        '(*2^128',
+        '\tAA',
+        '\rAA',
+        '\nAA',
+        'This+is+a/bad+base64Url==',
+        '0K3RgtC_INC30LDQutC_0LTQuNGA0L7QstCw0L3QvdCw0Y8g0YHRgtGA0L7QutCw',
+        'PDw_Pz8-Pg',
+      ],
+      error: [
+        null,
+        undefined,
+        {},
+        [],
+        42,
+      ],
+    });
+
     for (let i = 0, str = '', encoded; i < 1000; i++) {
       str += String.fromCharCode(Math.random() * 26 | 97); // eslint-disable-line no-bitwise
       encoded = Buffer.from(str).toString('base64');