added logic to keep query and hash upon redirect with preserveQuery flag

README.md

@@ -151,7 +151,7 @@ In order to redirect visits to a certain path to a different one (or even an ext
 }
 ```
 
-By default, all of them are performed with the status code [301](https://en.wikipedia.org/wiki/HTTP_301), but this behavior can be adjusted by setting the `type` property directly on the object (see below).
+By default, all of them are performed with the status code [301](https://en.wikipedia.org/wiki/HTTP_301), but this behavior can be adjusted by setting the `type` property directly on the object (see below). You may also add the flag `preserveQuery` in order to keep the query and hash upon redirect (for example, `/from?myParam=123#quote` by default routes to `/to`, but with `"preserveQuery": true` will route to `/to?myParam=123#quote`).
 
 Just like with [rewrites](#rewrites-array), you can also use routing segments:
 

src/index.js

@@ -170,13 +170,14 @@ const shouldRedirect = (decodedPath, {redirects = [], trailingSlash}, cleanUrl)
 	// This is currently the fastest way to
 	// iterate over an array
 	for (let index = 0; index < redirects.length; index++) {
-		const {source, destination, type} = redirects[index];
+		const {source, destination, type, preserveQuery} = redirects[index];
 		const target = toTarget(source, destination, decodedPath);
 
 		if (target) {
 			return {
 				target,
-				statusCode: type || defaultType
+				statusCode: type || defaultType,
+        preserveQuery: Boolean(preserveQuery)
 			};
 		}
 	}
@@ -583,8 +584,13 @@ module.exports = async (request, response, config = {}, methods = {}) => {
 	const redirect = shouldRedirect(relativePath, config, cleanUrl);
 
 	if (redirect) {
+		let Location = redirect.target
+    if (redirect.preserveQuery) {
+      const parsedUrl = url.parse(request.url)
+      Location = `${Location}${parsedUrl.search || ''}${parsedUrl.hash || ''}`
+    }
 		response.writeHead(redirect.statusCode, {
-			Location: encodeURI(redirect.target)
+			Location: encodeURI(Location)
 		});
 
 		response.end();