Fix init hook URLSearchParams deletions

Author: sindresorhus

source/core/Ky.ts

@@ -436,6 +436,14 @@ export class Ky {
 
 		if (hasSearchParameters(this.#options.searchParams)) {
 			const url = new URL(this.request.url);
+			const deleted = (this.#options.searchParams as any)?.[deletedParametersSymbol] as Set<string> | undefined;
+
+			if (deleted) {
+				// Remove keys from the input URL first so later searchParams entries can intentionally re-add them.
+				for (const key of deleted) {
+					url.searchParams.delete(key);
+				}
+			}
 
 			if (typeof this.#options.searchParams === 'string') {
 				const stringSearchParameters = this.#options.searchParams.replace(/^\?/, '');
@@ -463,13 +471,6 @@ export class Ky {
 				}
 			}
 
-			const deleted = (this.#options.searchParams as any)?.[deletedParametersSymbol] as Set<string> | undefined;
-			if (deleted) {
-				for (const key of deleted) {
-					url.searchParams.delete(key);
-				}
-			}
-
 			// Recreate request with the updated URL. We already have all options in this.#options, including duplex.
 			this.request = new globalThis.Request(url, this.#options as RequestInit);
 		}

source/utils/merge.ts

@@ -88,7 +88,14 @@ const isPlainObject = (value: unknown): value is Record<string, unknown> => {
 
 export const cloneShallow = <T>(value: T): T => {
 	if (value instanceof URLSearchParams) {
-		return new URLSearchParams(value) as T;
+		const copy = new URLSearchParams(value) as URLSearchParams & {[deletedParametersSymbol]?: Set<string>};
+		const deleted = (value as URLSearchParams & {[deletedParametersSymbol]?: Set<string>})[deletedParametersSymbol];
+		if (deleted) {
+			// Preserve internal deletion markers so init-hook cloning does not resurrect params removed during option merging.
+			copy[deletedParametersSymbol] = new Set(deleted);
+		}
+
+		return copy as T;
 	}
 
 	if (value instanceof globalThis.Headers) {

test/main.ts

@@ -1118,6 +1118,77 @@ test('init hook deletion over merged defaults and input URL', async t => {
 	t.false(url.searchParams.has('foo'));
 });
 
+test('init hook preserves merged URLSearchParams deletions', async t => {
+	const server = await createHttpTestServer(t);
+
+	server.get('/', (request, response) => {
+		response.end(request.url);
+	});
+
+	const api = ky.create({searchParams: new URLSearchParams({foo: '1'})}).extend({
+		searchParams: {foo: undefined},
+		hooks: {
+			init: [
+				() => {}, // eslint-disable-line @typescript-eslint/no-empty-function
+			],
+		},
+	});
+
+	const response = await api.get(`${server.url}?foo=from-url&bar=2`);
+	const url = new URL(await response.text(), server.url);
+
+	t.false(url.searchParams.has('foo'));
+	t.is(url.searchParams.get('bar'), '2');
+});
+
+test('init hook preserves merged plain object deletions', async t => {
+	const server = await createHttpTestServer(t);
+
+	server.get('/', (request, response) => {
+		response.end(request.url);
+	});
+
+	const api = ky.create({searchParams: {foo: '1'}}).extend({
+		searchParams: {foo: undefined},
+		hooks: {
+			init: [
+				() => {}, // eslint-disable-line @typescript-eslint/no-empty-function
+			],
+		},
+	});
+
+	const response = await api.get(`${server.url}?foo=from-url&bar=2`);
+	const url = new URL(await response.text(), server.url);
+
+	t.false(url.searchParams.has('foo'));
+	t.is(url.searchParams.get('bar'), '2');
+});
+
+test('init hook can re-add deleted URLSearchParams keys in place', async t => {
+	const server = await createHttpTestServer(t);
+
+	server.get('/', (request, response) => {
+		response.end(request.url);
+	});
+
+	const api = ky.create({searchParams: new URLSearchParams({foo: '1'})}).extend({
+		searchParams: {foo: undefined},
+		hooks: {
+			init: [
+				options => {
+					(options.searchParams as URLSearchParams).append('foo', '2');
+				},
+			],
+		},
+	});
+
+	const response = await api.get(`${server.url}?foo=from-url&bar=2`);
+	const url = new URL(await response.text(), server.url);
+
+	t.deepEqual(url.searchParams.getAll('foo'), ['2']);
+	t.is(url.searchParams.get('bar'), '2');
+});
+
 test('re-adding a key after an earlier deletion across merge layers', async t => {
 	const server = await createHttpTestServer(t);