From fafc2d269b01921bc4f649ee2524c0fe4a329199 Mon Sep 17 00:00:00 2001
From: Wes Roberts <me@jchook.com>
Date: Mon, 4 Dec 2017 22:23:12 -0500
Subject: [PATCH] [Fix] correctly parse nested arrays

Fixes #212.
---
 lib/utils.js  |  2 +-
 test/parse.js |  8 ++++++++
 test/utils.js | 24 ++++++++++++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/lib/utils.js b/lib/utils.js
index 6d5f440b..5958edc8 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -76,7 +76,7 @@ var merge = function merge(target, source, options) {
     if (Array.isArray(target) && Array.isArray(source)) {
         source.forEach(function (item, i) {
             if (has.call(target, i)) {
-                if (target[i] && typeof target[i] === 'object') {
+                if (target[i] && typeof target[i] === 'object' && item && typeof item === 'object') {
                     target[i] = merge(target[i], item, options);
                 } else {
                     target.push(item);
diff --git a/test/parse.js b/test/parse.js
index 74056e37..01a8ff47 100644
--- a/test/parse.js
+++ b/test/parse.js
@@ -237,6 +237,14 @@ test('parse()', function (t) {
         st.end();
     });
 
+    t.test('parses jquery-param strings', function (st) {
+        // readable = 'filter[0][]=int1&filter[0][]==&filter[0][]=77&filter[]=and&filter[2][]=int2&filter[2][]==&filter[2][]=8'
+        var encoded = 'filter%5B0%5D%5B%5D=int1&filter%5B0%5D%5B%5D=%3D&filter%5B0%5D%5B%5D=77&filter%5B%5D=and&filter%5B2%5D%5B%5D=int2&filter%5B2%5D%5B%5D=%3D&filter%5B2%5D%5B%5D=8';
+        var expected = { filter: [['int1', '=', '77'], 'and', ['int2', '=', '8']] };
+        st.deepEqual(qs.parse(encoded), expected);
+        st.end();
+    });
+
     t.test('continues parsing when no parent is found', function (st) {
         st.deepEqual(qs.parse('[]=&a=b'), { 0: '', a: 'b' });
         st.deepEqual(qs.parse('[]&a=b', { strictNullHandling: true }), { 0: null, a: 'b' });
diff --git a/test/utils.js b/test/utils.js
index 5c6056f2..f255de3f 100644
--- a/test/utils.js
+++ b/test/utils.js
@@ -21,6 +21,30 @@ test('merge()', function (t) {
     var noOptionsNonObjectSource = utils.merge({ foo: 'baz' }, 'bar');
     t.deepEqual(noOptionsNonObjectSource, { foo: 'baz', bar: true });
 
+    t.test(
+        'avoids invoking array setters unnecessarily',
+        { skip: typeof Object.defineProperty !== 'function' },
+        function (st) {
+            var setCount = 0;
+            var getCount = 0;
+            var observed = [];
+            Object.defineProperty(observed, 0, {
+                get: function () {
+                    getCount += 1;
+                    return { bar: 'baz' };
+                },
+                set: function () { setCount += 1; }
+            });
+            utils.merge(observed, [null]);
+            st.equal(setCount, 0);
+            st.equal(getCount, 2);
+            observed[0] = observed[0]; // eslint-disable-line no-self-assign
+            st.equal(setCount, 1);
+            st.equal(getCount, 3);
+            st.end();
+        }
+    );
+
     t.end();
 });