fix: preserve query string on automatic redirects

src/index.js

@@ -138,7 +138,8 @@ const shouldRedirect = (decodedPath, {redirects = [], trailingSlash}, cleanUrl)
 		}
 		return {
 			target: ensureSlashStart(decodedPath),
-			statusCode: defaultType
+			statusCode: defaultType,
+			preserveSearch: true
 		};
 	}
 
@@ -162,7 +163,8 @@ const shouldRedirect = (decodedPath, {redirects = [], trailingSlash}, cleanUrl)
 		if (target) {
 			return {
 				target: ensureSlashStart(target),
-				statusCode: defaultType
+				statusCode: defaultType,
+				preserveSearch: true
 			};
 		}
 	}
@@ -551,14 +553,17 @@ module.exports = async (request, response, config = {}, methods = {}) => {
 	const handlers = getHandlers(methods);
 
 	let relativePath = null;
+	let search = '';
 	let acceptsJSON = null;
 
 	if (request.headers.accept) {
 		acceptsJSON = request.headers.accept.includes('application/json');
 	}
 
 	try {
-		relativePath = decodeURIComponent(url.parse(request.url).pathname);
+		const parsedUrl = url.parse(request.url);
+		relativePath = decodeURIComponent(parsedUrl.pathname);
+		search = parsedUrl.search || '';
 	} catch (err) {
 		return sendError('/', response, acceptsJSON, current, handlers, config, {
 			statusCode: 400,
@@ -583,8 +588,10 @@ module.exports = async (request, response, config = {}, methods = {}) => {
 	const redirect = shouldRedirect(relativePath, config, cleanUrl);
 
 	if (redirect) {
+		const location = redirect.preserveSearch ? `${redirect.target}${search}` : redirect.target;
+
 		response.writeHead(redirect.statusCode, {
-			Location: encodeURI(redirect.target)
+			Location: encodeURI(location)
 		});
 
 		response.end();

test/integration.test.js

@@ -245,6 +245,22 @@ test('set `trailingSlash` config property to `true`', async () => {
 	expect(location).toBe(`${target}/`);
 });
 
+test('set `trailingSlash` config property to `true` and preserve query string', async () => {
+	const url = await getUrl({
+		trailingSlash: true
+	});
+
+	const target = `${url}/test?foo=bar`;
+
+	const response = await fetch(target, {
+		redirect: 'manual',
+		follow: 0
+	});
+
+	const location = response.headers.get('location');
+	expect(location).toBe(`${url}/test/?foo=bar`);
+});
+
 test('set `trailingSlash` config property to any boolean and remove multiple slashes', async () => {
 	const url = await getUrl({
 		trailingSlash: true
@@ -754,6 +770,22 @@ test('set `cleanUrls` config property to `true` and try with file', async () =>
 	expect(location).toBe(`${url}${target}`);
 });
 
+test('set `cleanUrls` config property to `true` and preserve query string', async () => {
+	const target = '/directory/clean-file';
+
+	const url = await getUrl({
+		cleanUrls: true
+	});
+
+	const response = await fetch(`${url}${target}.html?foo=bar`, {
+		redirect: 'manual',
+		follow: 0
+	});
+
+	const location = response.headers.get('location');
+	expect(location).toBe(`${url}${target}?foo=bar`);
+});
+
 test('set `cleanUrls` config property to `true` and not index file found', async () => {
 	const contents = await getDirectoryContents();
 	const url = await getUrl({cleanUrls: true});