[update] stringify with comma:true to decode comma for an array as a reserved char per RFC3986

Author: Mohamed Omar

lib/stringify.js

@@ -74,8 +74,6 @@ var stringify = function stringify(
         obj = filter(prefix, obj);
     } else if (obj instanceof Date) {
         obj = serializeDate(obj);
-    } else if (generateArrayPrefix === 'comma' && isArray(obj)) {
-        obj = obj.join(',');
     }
 
     if (obj === null) {
@@ -94,6 +92,17 @@ var stringify = function stringify(
         return [formatter(prefix) + '=' + formatter(String(obj))];
     }
 
+    if (generateArrayPrefix === 'comma' && isArray(obj)) {
+        if (encoder) {
+            var commaKey = encodeValuesOnly ? prefix : encoder(prefix, defaults.encoder, charset, 'key');
+            var commaValue = obj.map(function (item) {
+                return formatter(encoder(item, defaults.encoder, charset, 'value'));
+            });
+            return [formatter(commaKey) + '=' + commaValue];
+        }
+        return [formatter(prefix) + '=' + formatter(String(obj))];
+    }
+
     var values = [];
 
     if (typeof obj === 'undefined') {

test/stringify.js

@@ -105,7 +105,7 @@ test('stringify()', function (t) {
         );
         st.equal(
             qs.stringify({ a: ['b', 'c', 'd'] }, { arrayFormat: 'comma' }),
-            'a=b%2Cc%2Cd',
+            'a=b,c,d',
             'comma => comma'
         );
         st.equal(
@@ -134,7 +134,7 @@ test('stringify()', function (t) {
     t.test('stringifies a nested array value', function (st) {
         st.equal(qs.stringify({ a: { b: ['c', 'd'] } }, { arrayFormat: 'indices' }), 'a%5Bb%5D%5B0%5D=c&a%5Bb%5D%5B1%5D=d');
         st.equal(qs.stringify({ a: { b: ['c', 'd'] } }, { arrayFormat: 'brackets' }), 'a%5Bb%5D%5B%5D=c&a%5Bb%5D%5B%5D=d');
-        st.equal(qs.stringify({ a: { b: ['c', 'd'] } }, { arrayFormat: 'comma' }), 'a%5Bb%5D=c%2Cd'); // a[b]=c,d
+        st.equal(qs.stringify({ a: { b: ['c', 'd'] } }, { arrayFormat: 'comma' }), 'a%5Bb%5D=c,d'); // a[b]=c,d
         st.equal(qs.stringify({ a: { b: ['c', 'd'] } }), 'a%5Bb%5D%5B0%5D=c&a%5Bb%5D%5B1%5D=d');
         st.end();
     });