From 9e2ac7bed85c3489697204aba3d2f4b718622b93 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 16 Jan 2026 09:08:06 +0000
Subject: [PATCH 1/3] Initial plan


From 48e701878efaff3a3c3265bac1ace833b9aea1b5 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 16 Jan 2026 09:12:20 +0000
Subject: [PATCH 2/3] fix: prevent double encoding in nested query params at 3+
 levels

Co-authored-by: bnachtweh <32386227+bnachtweh@users.noreply.github.com>
---
 src/url.ts        | 10 ++++++----
 tests/url.spec.ts | 23 +++++++++++++++++++++++
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/url.ts b/src/url.ts
index 425c7e9..d025c62 100644
--- a/src/url.ts
+++ b/src/url.ts
@@ -31,13 +31,13 @@ function stringify(
         return queryString;
       }
 
-      const encodedKey = prefix
-        ? encodeURIComponent(`${prefix}[${key}]`)
-        : encodeURIComponent(key);
+      // Build the unencoded key path first
+      const keyPath = prefix ? `${prefix}[${key}]` : key;
 
       // Check if value is an object and we haven't exceeded max depth
       if (typeof value === "object" && value !== null && depth < maxDepth) {
-        const nestedQuery = stringifyRecursive(value, encodedKey, depth + 1);
+        // Pass unencoded keyPath as prefix for recursion
+        const nestedQuery = stringifyRecursive(value, keyPath, depth + 1);
 
         // Only append if nestedQuery has content
         if (!nestedQuery) {
@@ -48,6 +48,8 @@ function stringify(
           ? `${queryString}${separator}${nestedQuery}`
           : nestedQuery;
       } else {
+        // Encode only once at the leaf level
+        const encodedKey = encodeURIComponent(keyPath);
         const encodedValue =
           typeof value === "object" && value !== null
             ? ""
diff --git a/tests/url.spec.ts b/tests/url.spec.ts
index 7561530..1040188 100644
--- a/tests/url.spec.ts
+++ b/tests/url.spec.ts
@@ -195,4 +195,27 @@ describe("DynamicURL", () => {
     expect(result).toBe("https://example.com?citizen=robespierre");
     expect(result).not.toContain("emptyNested");
   });
+
+  test("should not double-encode nested objects at 3+ levels deep", () => {
+    const url = new DynamicURL("https://example.com");
+    url.setQueryParams({
+      level1: {
+        level2: {
+          level3: "value",
+        },
+      },
+    });
+
+    const result = url.resolve();
+    // Should have single encoding: level1[level2][level3]
+    expect(result).toBe(
+      "https://example.com?level1%5Blevel2%5D%5Blevel3%5D=value"
+    );
+
+    // Verify decoded key is correct
+    const queryString = result.split("?")[1];
+    const params = new URLSearchParams(queryString);
+    const keys = Array.from(params.keys());
+    expect(keys[0]).toBe("level1[level2][level3]");
+  });
 });

From 3476edc96e7abdb84e6385cfe9f4bffd1071749f Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 16 Jan 2026 09:13:31 +0000
Subject: [PATCH 3/3] docs: improve comment clarity for double encoding
 prevention

Co-authored-by: bnachtweh <32386227+bnachtweh@users.noreply.github.com>
---
 src/url.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/url.ts b/src/url.ts
index d025c62..4738ac9 100644
--- a/src/url.ts
+++ b/src/url.ts
@@ -36,7 +36,7 @@ function stringify(
 
       // Check if value is an object and we haven't exceeded max depth
       if (typeof value === "object" && value !== null && depth < maxDepth) {
-        // Pass unencoded keyPath as prefix for recursion
+        // Pass unencoded keyPath as prefix to prevent double encoding in recursive calls
         const nestedQuery = stringifyRecursive(value, keyPath, depth + 1);
 
         // Only append if nestedQuery has content