fix: enhance req.acceptsCharsets method (#6088)

* fix: enhance req.acceptsCharsets method

* Update req.acceptsCharsets.js

---------

Co-authored-by: Monaam Aouini <[email protected]>
Co-authored-by: Sebastian Beltran <[email protected]>

Author: 3 people

lib/request.js

@@ -147,17 +147,34 @@ req.acceptsEncodings = function(){
 };
 
 /**
- * Check if the given `charset`s are acceptable,
- * otherwise you should respond with 406 "Not Acceptable".
+ * Checks if the specified `charset`s are acceptable based on the request's `Accept-Charset` header.
+ * Returns the best matching charset or an array of acceptable charsets.
  *
- * @param {String} ...charset
- * @return {String|Array}
+ * The `charset` argument(s) can be:
+ * - A single charset string (e.g., "utf-8")
+ * - Multiple charset strings as arguments (e.g., `"utf-8", "iso-8859-1"`)
+ * - A comma-delimited list of charsets (e.g., `"utf-8, iso-8859-1"`)
+ *
+ * Examples:
+ *
+ *     // Accept-Charset: utf-8, iso-8859-1
+ *     req.acceptsCharsets('utf-8');
+ *     // => "utf-8"
+ *
+ *     req.acceptsCharsets('utf-8', 'iso-8859-1');
+ *     // => "utf-8"
+ *
+ *     req.acceptsCharsets('utf-8, utf-16');
+ *     // => "utf-8"
+ *
+ * @param {...String} charsets - The charset(s) to check against the `Accept-Charset` header.
+ * @return {String|Array} - The best matching charset, or an array of acceptable charsets.
  * @public
  */
 
-req.acceptsCharsets = function(){
-  var accept = accepts(this);
-  return accept.charsets.apply(accept, arguments);
+req.acceptsCharsets = function(...charsets) {
+  const accept = accepts(this);
+  return accept.charsets(...charsets);
 };
 
 /**

test/req.acceptsCharsets.js

@@ -45,6 +45,19 @@ describe('req', function(){
         .set('Accept-Charset', 'foo, bar')
         .expect('no', done);
       })
+
+      it('should return the best matching charset from multiple inputs', function (done) {
+        var app = express();
+
+        app.use(function(req, res, next){
+          res.end(req.acceptsCharsets('utf-8', 'iso-8859-1'));
+        });
+
+        request(app)
+        .get('/')
+        .set('Accept-Charset', 'iso-8859-1, utf-8')
+        .expect('iso-8859-1', done);
+      })
     })
   })
 })