feat(rss): add option to remove the trailing slash

.changeset/popular-rules-divide.md

@@ -0,0 +1,17 @@
+---
+'@astrojs/rss': minor
+---
+
+Added `trailingSlash` option, to control whether the emitted URLs should have the trailing slash.
+
+The new option is optional. Values accepted are: `"always"` and `"never"`.
+
+```js
+import rss from '@astrojs/rss';
+
+export const get = () => rss({
+  trailingSlash: "never"
+});
+```
+
+By passing `"never"`, the emitted links won't have the trailing slash.

packages/astro-rss/README.md

@@ -73,6 +73,8 @@ export function get(context) {
     customData: '<language>en-us</language>',
     // (optional) add arbitrary metadata to opening <rss> tag
     xmlns: { h: 'http://www.w3.org/TR/html4/' },
+    // (optional) add or not the trailing slash
+    trailingSlash: "never"
   });
 }
 ```
@@ -233,6 +235,22 @@ export async function get(context) {
 }
 ```
 
+### `trailingSlash`
+
+Type: `"nevery" | "always" (optional)`
+Default: "always"
+
+By default, the library will add trailing slashes to the emitted URLs. To change this behaviour,
+you use this option, by passing the value `"never"`.
+
+```js
+import rss from '@astrojs/rss';
+
+export const get = () => rss({
+  trailingSlash: "never"
+});
+```
+
 ---
 
 For more on building with Astro, [visit the Astro docs][astro-rss].

packages/astro-rss/src/index.ts

@@ -29,6 +29,7 @@ export type RSSOptions = {
 	customData?: z.infer<typeof rssOptionsValidator>['customData'];
 	/** Whether to include drafts or not */
 	drafts?: z.infer<typeof rssOptionsValidator>['drafts'];
+	trailingSlash?: z.infer<typeof rssOptionsValidator>['trailingSlash'];
 };
 
 type RSSFeedItem = {
@@ -54,6 +55,7 @@ type GlobResult = z.infer<typeof globResultValidator>;
 
 const rssFeedItemValidator = rssSchema.extend({ link: z.string(), content: z.string().optional() });
 const globResultValidator = z.record(z.function().returns(z.promise(z.any())));
+const TRAILING_SLASH = ['always', 'never'] as const;
 const rssOptionsValidator = z.object({
 	title: z.string(),
 	description: z.string(),
@@ -77,6 +79,7 @@ const rssOptionsValidator = z.object({
 	drafts: z.boolean().default(false),
 	stylesheet: z.union([z.string(), z.boolean()]).optional(),
 	customData: z.string().optional(),
+	trailingSlash: z.enum(TRAILING_SLASH).optional(),
 });
 
 export default async function getRSS(rssOptions: RSSOptions) {
@@ -171,7 +174,7 @@ async function generateRSS(rssOptions: ValidatedRSSOptions): Promise<string> {
 	root.rss.channel = {
 		title: rssOptions.title,
 		description: rssOptions.description,
-		link: createCanonicalURL(site).href,
+		link: createCanonicalURL(site, rssOptions.trailingSlash, undefined).href,
 	};
 	if (typeof rssOptions.customData === 'string')
 		Object.assign(
@@ -183,7 +186,7 @@ async function generateRSS(rssOptions: ValidatedRSSOptions): Promise<string> {
 		// If the item's link is already a valid URL, don't mess with it.
 		const itemLink = isValidURL(result.link)
 			? result.link
-			: createCanonicalURL(result.link, site).href;
+			: createCanonicalURL(result.link, rssOptions.trailingSlash, site).href;
 		const item: any = {
 			title: result.title,
 			link: itemLink,

packages/astro-rss/src/util.ts

@@ -1,10 +1,23 @@
 import { z } from 'astro/zod';
+import { RSSOptions } from './index';
 
 /** Normalize URL to its canonical form */
-export function createCanonicalURL(url: string, base?: string): URL {
+export function createCanonicalURL(
+	url: string,
+	trailingSlash?: RSSOptions['trailingSlash'],
+	base?: string
+): URL {
 	let pathname = url.replace(/\/index.html$/, ''); // index.html is not canonical
 	pathname = pathname.replace(/\/1\/?$/, ''); // neither is a trailing /1/ (impl. detail of collections)
-	if (!getUrlExtension(url)) pathname = pathname.replace(/(\/+)?$/, '/'); // add trailing slash if there’s no extension
+	if (trailingSlash !== 'never') {
+		// add trailing slash if there’s no extension
+		if (!getUrlExtension(url) || trailingSlash === 'always')
+			pathname = pathname.replace(/(\/+)?$/, '/');
+	} else {
+		// remove the trailing slash
+		pathname = pathname.replace(/(\/+)?$/, '');
+	}
+
 	pathname = pathname.replace(/\/+/g, '/'); // remove duplicate slashes (URL() won’t)
 	return new URL(pathname, base);
 }

packages/astro-rss/test/rss.test.js

@@ -107,7 +107,6 @@ describe('rss', () => {
 		const { body } = await rss({
 			title,
 			description,
-			drafts: true,
 			items: [phpFeedItem, { ...web1FeedItem, draft: true }],
 			site,
 			drafts: true,
@@ -116,6 +115,20 @@ describe('rss', () => {
 		chai.expect(body).xml.to.equal(validXmlResult);
 	});
 
+	it('should not append trailing slash to URLs with the given option', async () => {
+		const { body } = await rss({
+			title,
+			description,
+			items: [phpFeedItem, { ...web1FeedItem, draft: true }],
+			site,
+			drafts: true,
+			trailingSlash: 'never',
+		});
+
+		chai.expect(body).xml.to.contain('https://example.com/<');
+		chai.expect(body).xml.to.contain('https://example.com/php<');
+	});
+
 	it('Deprecated import.meta.glob mapping still works', async () => {
 		const globResult = {
 			'./posts/php.md': () =>