feat(underscore-redirects): add base to input paths (#8953)

Co-authored-by: Sarah Rainsberger <5098874+sarah11918@users.noreply.github.com>
Co-authored-by: Bjorn Lu <34116392+bluwy@users.noreply.github.com>

.changeset/odd-maps-glow.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/underscore-redirects': patch
+---
+
+Adds the base path as prefix for input paths

packages/underscore-redirects/src/astro.ts

@@ -12,7 +12,7 @@ function getRedirectStatus(route: RouteData): ValidRedirectStatus {
 }
 
 interface CreateRedirectsFromAstroRoutesParams {
-	config: Pick<AstroConfig, 'build' | 'output'>;
+	config: Pick<AstroConfig, 'build' | 'output' | 'base'>;
 	/**
 	 * Maps a `RouteData` to a dynamic target
 	 */
@@ -28,6 +28,12 @@ export function createRedirectsFromAstroRoutes({
 	routeToDynamicTargetMap,
 	dir,
 }: CreateRedirectsFromAstroRoutesParams) {
+	const base =
+		config.base && config.base !== '/'
+			? config.base.endsWith('/')
+				? config.base.slice(0, -1)
+				: config.base
+			: '';
 	const output = config.output;
 	const _redirects = new Redirects();
 
@@ -39,7 +45,7 @@ export function createRedirectsFromAstroRoutes({
 				// from the user if provided.
 				_redirects.add({
 					dynamic: false,
-					input: route.pathname,
+					input: `${base}${route.pathname}`,
 					target: typeof route.redirect === 'object' ? route.redirect.destination : route.redirect,
 					status: getRedirectStatus(route),
 					weight: 2,
@@ -53,15 +59,15 @@ export function createRedirectsFromAstroRoutes({
 			} else if (route.distURL) {
 				_redirects.add({
 					dynamic: false,
-					input: route.pathname,
+					input: `${base}${route.pathname}`,
 					target: prependForwardSlash(route.distURL.toString().replace(dir.toString(), '')),
 					status: 200,
 					weight: 2,
 				});
 			} else {
 				_redirects.add({
 					dynamic: false,
-					input: route.pathname,
+					input: `${base}${route.pathname}`,
 					target: dynamicTarget,
 					status: 200,
 					weight: 2,
@@ -94,15 +100,15 @@ export function createRedirectsFromAstroRoutes({
 				}
 				_redirects.add({
 					dynamic: true,
-					input: pattern,
+					input: `${base}${route.pattern}`,
 					target,
 					status: route.type === 'redirect' ? 301 : 200,
 					weight: 1,
 				});
 			} else {
 				_redirects.add({
 					dynamic: true,
-					input: pattern,
+					input: `${base}${route.pattern}`,
 					target: dynamicTarget,
 					status: 200,
 					weight: 1,