[New] [Fix] stringify: revert 0e903c0; add commaRoundTrip option

Fixes #442. See #441, #434.
ljharb · Jun 27, 2022 · c313472 · c313472
1 parent 95bc018
commit c313472
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Showing 4 changed files with 30 additions and 6 deletions.
diff --git a/.eslintrc b/.eslintrc
@@ -14,7 +14,7 @@
         "id-length": [2, { "min": 1, "max": 25, "properties": "never" }],
         "indent": [2, 4],
         "max-lines-per-function": [2, { "max": 150 }],
-        "max-params": [2, 15],
+        "max-params": [2, 16],
         "max-statements": [2, 53],
         "multiline-comment-style": 0,
         "no-continue": 1,

diff --git a/README.md b/README.md
@@ -402,6 +402,8 @@ qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'comma' })
 // 'a=b,c'
 ```
 
+Note: when using `arrayFormat` set to `'comma'`, you can also pass the `commaRoundTrip` option set to `true` or `false`, to append `[]` on single-item arrays, so that they can round trip through a parse.
+
 When objects are stringified, by default they use bracket notation:
 
 ```javascript

diff --git a/lib/stringify.js b/lib/stringify.js
@@ -62,6 +62,7 @@ var stringify = function stringify(
     object,
     prefix,
     generateArrayPrefix,
+    commaRoundTrip,
     strictNullHandling,
     skipNulls,
     encoder,
@@ -126,7 +127,7 @@ var stringify = function stringify(
                 for (var i = 0; i < valuesArray.length; ++i) {
                     valuesJoined += (i === 0 ? '' : ',') + formatter(encoder(valuesArray[i], defaults.encoder, charset, 'value', format));
                 }
-                return [formatter(keyValue) + (isArray(obj) && valuesArray.length === 1 ? '[]' : '') + '=' + valuesJoined];
+                return [formatter(keyValue) + (commaRoundTrip && isArray(obj) && valuesArray.length === 1 ? '[]' : '') + '=' + valuesJoined];
             }
             return [formatter(keyValue) + '=' + formatter(encoder(obj, defaults.encoder, charset, 'value', format))];
         }
@@ -150,7 +151,7 @@ var stringify = function stringify(
         objKeys = sort ? keys.sort(sort) : keys;
     }
 
-    var adjustedPrefix = generateArrayPrefix === 'comma' && isArray(obj) && obj.length === 1 ? prefix + '[]' : prefix;
+    var adjustedPrefix = commaRoundTrip && isArray(obj) && obj.length === 1 ? prefix + '[]' : prefix;
 
     for (var j = 0; j < objKeys.length; ++j) {
         var key = objKeys[j];
@@ -171,6 +172,7 @@ var stringify = function stringify(
             value,
             keyPrefix,
             generateArrayPrefix,
+            commaRoundTrip,
             strictNullHandling,
             skipNulls,
             encoder,
@@ -267,6 +269,10 @@ module.exports = function (object, opts) {
     }
 
     var generateArrayPrefix = arrayPrefixGenerators[arrayFormat];
+    if (opts && 'commaRoundTrip' in opts && typeof opts.commaRoundTrip !== 'boolean') {
+        throw new TypeError('`commaRoundTrip` must be a boolean, or absent');
+    }
+    var commaRoundTrip = generateArrayPrefix === 'comma' && opts && opts.commaRoundTrip;
 
     if (!objKeys) {
         objKeys = Object.keys(obj);
@@ -287,6 +293,7 @@ module.exports = function (object, opts) {
             obj[key],
             key,
             generateArrayPrefix,
+            commaRoundTrip,
             options.strictNullHandling,
             options.skipNulls,
             options.encode ? options.encoder : null,

diff --git a/test/stringify.js b/test/stringify.js
@@ -144,7 +144,8 @@ test('stringify()', function (t) {
         st.test('array with a single item', function (s2t) {
             s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true, arrayFormat: 'indices' }), 'a[0]=c');
             s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a[]=c');
-            s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true, arrayFormat: 'comma' }), 'a[]=c'); // so it parses back as an array
+            s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true, arrayFormat: 'comma' }), 'a=c');
+            s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true, arrayFormat: 'comma', commaRoundTrip: true }), 'a[]=c'); // so it parses back as an array
             s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true }), 'a[0]=c');
 
             s2t.end();
@@ -379,12 +380,14 @@ test('stringify()', function (t) {
         st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'indices' }), 'b[0]=&c=c');
         st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'brackets' }), 'b[]=&c=c');
         st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'repeat' }), 'b=&c=c');
-        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma' }), 'b[]=&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma' }), 'b=&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma', commaRoundTrip: true }), 'b[]=&c=c');
         // with strictNullHandling
         st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'indices', strictNullHandling: true }), 'b[0]&c=c');
         st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'brackets', strictNullHandling: true }), 'b[]&c=c');
         st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'repeat', strictNullHandling: true }), 'b&c=c');
-        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma', strictNullHandling: true }), 'b[]&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma', strictNullHandling: true }), 'b&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma', strictNullHandling: true, commaRoundTrip: true }), 'b[]&c=c');
         // with skipNulls
         st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'indices', skipNulls: true }), 'c=c');
         st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'brackets', skipNulls: true }), 'c=c');
@@ -712,6 +715,18 @@ test('stringify()', function (t) {
                     arrayFormat: 'comma'
                 }
             ),
+            'a=' + date.getTime(),
+            'works with arrayFormat comma'
+        );
+        st.equal(
+            qs.stringify(
+                { a: [date] },
+                {
+                    serializeDate: function (d) { return d.getTime(); },
+                    arrayFormat: 'comma',
+                    commaRoundTrip: true
+                }
+            ),
             'a%5B%5D=' + date.getTime(),
             'works with arrayFormat comma'
         );