feat: add HTTP response and parsing helpers for form-based UX flows

test/http.test.js

@@ -0,0 +1,31 @@
+"use strict";
+
+const test = require("node:test");
+const assert = require("node:assert/strict");
+const {
+  redirect,
+  parseJSON,
+  parseFormUrlEncoded,
+  withQuery,
+} = require("../src/lib/http");
+
+test("redirect returns 303 and location", () => {
+  const response = redirect("/app");
+  assert.equal(response.status, 303);
+  assert.equal(response.headers.location, "/app");
+});
+
+test("parseJSON throws on invalid payload", () => {
+  assert.throws(() => parseJSON("{invalid}"), /invalid_json/);
+});
+
+test("parseFormUrlEncoded parses plus and percent encoding", () => {
+  const body = "title=Hello+World&body=Line%201%0ALine%202";
+  const parsed = parseFormUrlEncoded(body);
+  assert.equal(parsed.title, "Hello World");
+  assert.equal(parsed.body, "Line 1\nLine 2");
+});
+
+test("withQuery appends query params", () => {
+  assert.equal(withQuery("/login", { returnTo: "/audio/1", flash: "done" }), "/login?returnTo=%2Faudio%2F1&flash=done");
+});