Throw if the charset is not one of the two supported values or undefined

ljharb#268 (comment)

Author: papandreou

lib/parse.js

@@ -45,6 +45,9 @@ var parseValues = function parseQueryStringValues(str, options) {
     var skipIndex = -1; // Keep track of where the utf8 sentinel was found
     var i;
 
+    if (charset !== undefined && charset !== 'utf-8' && charset !== 'iso-8859-1') {
+        throw new Error('The charset option must be either utf-8, iso-8859-1, or undefined');
+    }
     if (options.utf8Sentinel) {
         for (i = 0; i < parts.length; ++i) {
             if (parts[i].indexOf('utf8=') === 0) {

test/parse.js

@@ -577,6 +577,13 @@ test('parse()', function (t) {
         st.end();
     });
 
+    t.test('throws if an invalid charset is specified', function (st) {
+        st['throws'](function () {
+            qs.parse('a=b', { charset: 'foobar' });
+        }, new TypeError('The charset option must be either utf-8, iso-8859-1, or undefined'));
+        st.end();
+    });
+
     t.test('parses an iso-8859-1 string if asked to', function (st) {
         st.deepEqual(qs.parse('%A2=%BD', { charset: 'iso-8859-1' }), { '¢': '½' });
         st.end();