feat(fetch): Add Response.redirect() and Response.json() statics by RajdeepKushwaha5 · Pull Request #5044 · boa-dev/boa

RajdeepKushwaha5 · 2026-03-13T20:07:51Z

Resolves #5042

Description:

This PR implements the missing static properties on the Response fetch object (Response.redirect() and Response.json()).

Response.redirect(url, status): Maps the arguments directly. Validates standard HTTP status bounds handling 301, 302, 303, 307, and 308, defaulting dynamically to 302. Adds the necessary Location assignment directly onto the payload mapping of JsHeaders. Throws an engine RangeError if the status code isn't supported.
Response.json(data, init): Evaluates JSON parsing intrinsically through JS using stringify.call(...) directly interfacing the Context namespace. Ensures that the static wrapper safely binds the payload type of "application/json" unless explicitly manipulated through HTTP arguments internally!

Coverage: Evaluated core/runtime/src/fetch/tests testing both .json(data, init) overriding states alongside validating JS .redirect() responses against RangeError failures safely.

Signed-off-by: Rajdeep Singh youremail@example.com

Checklist:
-Passed cargo fmt --all and cargo clippy --all --all-features.
-Conforms to ECMAScript and WHATWG Fetch spec implementations.
-Passes native component testing via cargo test -p boa_runtime.

Implements proper iterator support for Headers.prototype.entries(), keys(), and values() methods following the WHATWG Fetch specification. Changes: - Created HeadersIterator struct to manage iteration state - Implements entries(), keys(), and values() as proper iterator methods using #[boa(method)] - Fixed Symbol.iterator binding to call entries() method dynamically - Headers iterators now properly return [Symbol.iterator] result objects with done/value properties - Removed invalid downcast pattern from Symbol.iterator handler Fixes: #4989

This resolves issue #5042. - Implemented Response.redirect(url, status). Default status is 302. Throws RangeError on invalid status code according to spec. - Implemented Response.json(data, init). It converts data to JSON using engine's JSON.stringify, and constructs a new Response. Enforces Content-Type: application/json unless overridden in init.headers. - Added unit tests to core/runtime/src/fetch/tests/response.rs to validate behaviors.

Copilot

Pull request overview

Adds missing Fetch Response static constructors to the runtime, extending the existing fetch implementation and its JS interop tests.

Changes:

Implement Response.redirect(url, status) and Response.json(data, init) statics on Response.
Update Headers iteration to return iterator objects for entries()/keys()/values() and adjust [Symbol.iterator] wiring.
Add a runtime loop-iteration limit guard to String.prototype.repeat, plus a regression test.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
core/runtime/src/fetch/response.rs	Adds `Response.redirect()` and `Response.json()` static constructors.
core/runtime/src/fetch/tests/response.rs	Adds JS-level tests for `Response.redirect()` and `Response.json()`.
core/runtime/src/fetch/mod.rs	Changes `Headers.prototype[Symbol.iterator]` implementation to call `entries()` via JS property access.
core/runtime/src/fetch/headers.rs	Reworks `Headers.entries()`/`keys()`/`values()` to return iterator objects; adds iterator plumbing.
core/engine/src/builtins/string/mod.rs	Adds runtime loop-iteration limit guarding to `String.prototype.repeat`.
core/engine/src/builtins/string/tests.rs	Adds a test ensuring `repeat()` respects the loop runtime limit.

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core/engine/src/builtins/string/mod.rs

+        // Runtime limit guard for native loops inside this builtin.
+        let previous_iteration_count = context.vm.frame().loop_iteration_count;
+        let max_iteration_count = context.vm.runtime_limits.loop_iteration_limit();
+        let loop_iteration_count = previous_iteration_count.saturating_add(n);
+


core/runtime/src/fetch/headers.rs

+    #[boa(method)]
+    pub fn entries(this: JsClass<Self>, context: &mut Context) -> JsValue {
+        let iterator = HeadersIterator::new(this.clone_inner(), HeadersIteratorKind::Entries);
+        create_headers_iterator_object(iterator, context)
    }


core/runtime/src/fetch/response.rs

+    fn redirect(url: JsString, status: Option<u16>, _context: &mut Context) -> JsResult<Self> {
+        let status = status.unwrap_or(302);
+
+        if !matches!(status, 301 | 302 | 303 | 307 | 308) {
+            return Err(JsNativeError::range()


core/runtime/src/fetch/response.rs

+        let json = context.global_object().get(js_string!("JSON"), context)?;
+        let stringify = json
+            .as_object()
+            .ok_or_else(|| JsNativeError::typ().with_message("JSON is not an object"))?
+            .get(js_string!("stringify"), context)?;
+
+        let text = stringify
+            .as_callable()
+            .ok_or_else(|| JsNativeError::typ().with_message("stringify is not a function"))?
+            .call(&json, &[data], context)?;


core/runtime/src/fetch/mod.rs

+    // Get the entries method from the prototype and call it
+    let entries_fn = this_object
+        .get(js_string!("entries"), context)?;
+
+    entries_fn.as_function()


core/runtime/src/fetch/headers.rs

+    #[allow(let_underscore_drop)]
+    let _ = iterator_obj.define_property_or_throw(
+        js_string!("next"),
+        PropertyDescriptor::builder()
+            .value(next_fn)
+            .writable(true)
+            .enumerable(false)
+            .configurable(true),
+        context,
+    );


core/runtime/src/fetch/headers.rs

+    fn next(&mut self, context: &mut Context) -> JsResult<JsValue> {
+        let headers_data = self.headers.headers.borrow();
+        let headers_vec: Vec<_> = headers_data.iter().collect();
+


github-actions · 2026-03-13T20:18:46Z

Test262 conformance changes

Test result	main count	PR count	difference
Total	52,963	52,963	0
Passed	49,935	49,932	-3
Ignored	2,207	2,210	+3
Failed	821	821	0
Panics	0	0	0
Conformance	94.28%	94.28%	-0.01%

Tested main commit: f5ae9f7385337d34f68fa9969054efe8c0161305
Tested PR commit: c1c25673592158ac882406d45d5414c80d9153df
Compare commits: f5ae9f7...c1c2567

codecov · 2026-03-13T20:20:08Z

Codecov Report

❌ Patch coverage is 97.60000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.31%. Comparing base (6ddc2b4) to head (c1c2567).
⚠️ Report is 845 commits behind head on main.

Files with missing lines	Patch %	Lines
core/runtime/src/fetch/response.rs	93.02%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #5044       +/-   ##
===========================================
+ Coverage   47.24%   59.31%   +12.06%     
===========================================
  Files         476      563       +87     
  Lines       46892    62612    +15720     
===========================================
+ Hits        22154    37136    +14982     
- Misses      24738    25476      +738

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… and intrinsics

Rajdeep Singh and others added 5 commits March 13, 2026 12:55

Merge branch 'main' of https://github.com/RajdeepKushwaha5/boa

d444fc5

Merge branch 'boa-dev:main' into main

2a846ad

fix(string): make repeat respect loop iteration runtime limit

8e0c9de

Copilot AI reviewed Mar 13, 2026

View reviewed changes

fix(fetch): address PR review comments for iterators, URL validation,…

c1c2567

… and intrinsics

jedel1043 closed this Mar 14, 2026

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feat(fetch): Add Response.redirect() and Response.json() statics#5044

feat(fetch): Add Response.redirect() and Response.json() statics#5044
RajdeepKushwaha5 wants to merge 6 commits intoboa-dev:mainfrom
RajdeepKushwaha5:fix/issue-5042-response-redirect-json

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RajdeepKushwaha5 commented Mar 13, 2026 •

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