Fix alternative index.html path

Author: JoviDeCroock

src/plugins/prerender-plugin.js

@@ -75,6 +75,7 @@ export function prerenderPlugin({ prerenderScript, renderTarget, additionalPrere
     let viteConfig = {};
     let userEnabledSourceMaps;
     let ssrBuild = false;
+    let prerenderEntryHtml;
 
     /** @type {import('./types.d.ts').PrerenderedRoute[]} */
     let routes = [];
@@ -90,12 +91,9 @@ export function prerenderPlugin({ prerenderScript, renderTarget, additionalPrere
     const tmpDirId = 'headless-prerender';
 
     /**
-     * From the non-external scripts in entry HTML document, find the one (if any)
-     * that provides a `prerender` export
-     *
      * @param {import('vite').Rollup.InputOption} input
      */
-    const getPrerenderScriptFromHTML = async (input) => {
+    const getPrerenderEntryHtml = (input) => {
         // prettier-ignore
         const entryHtml =
             typeof input === "string"
@@ -106,6 +104,17 @@ export function prerenderPlugin({ prerenderScript, renderTarget, additionalPrere
 
         if (!entryHtml) throw new Error('Unable to detect entry HTML');
 
+        return path.resolve(viteConfig.root, entryHtml);
+    };
+
+    /**
+     * From the non-external scripts in entry HTML document, find the one (if any)
+     * that provides a `prerender` export
+     *
+     * @param {import('vite').Rollup.InputOption} input
+     */
+    const getPrerenderScriptFromHTML = async (input) => {
+        const entryHtml = getPrerenderEntryHtml(input);
         const htmlDoc = htmlParse(await fs.readFile(entryHtml, 'utf-8'));
 
         const entryScriptTag = htmlDoc
@@ -118,7 +127,9 @@ export function prerenderPlugin({ prerenderScript, renderTarget, additionalPrere
         if (!entrySrc || /^https:/.test(entrySrc))
             throw new Error('Prerender entry script must have a `src` attribute and be local');
 
-        return path.join(viteConfig.root, entrySrc);
+        return entrySrc.startsWith('/')
+            ? path.join(viteConfig.root, entrySrc)
+            : path.resolve(path.dirname(entryHtml), entrySrc);
     };
 
     return {
@@ -194,6 +205,7 @@ export function prerenderPlugin({ prerenderScript, renderTarget, additionalPrere
         },
         async options(opts) {
             if (ssrBuild || !opts.input) return;
+            prerenderEntryHtml = getPrerenderEntryHtml(opts.input);
             if (!prerenderScript) {
                 prerenderScript = await getPrerenderScriptFromHTML(opts.input);
             }
@@ -288,9 +300,25 @@ export function prerenderPlugin({ prerenderScript, renderTarget, additionalPrere
             };
 
             // Grab the generated HTML file, we'll use it as a template for all pages:
-            const tpl = /** @type {string} */ (
-                /** @type {OutputAsset} */ (bundle['index.html']).source
-            );
+            const entryHtmlAsset =
+                (prerenderEntryHtml &&
+                    Object.values(bundle).find(
+                        (output) =>
+                            output.type === 'asset' &&
+                            output.fileName.endsWith('.html') &&
+                            (output.originalFileName === prerenderEntryHtml ||
+                                output.originalFileNames?.includes(prerenderEntryHtml)),
+                    )) ||
+                bundle['index.html'] ||
+                Object.values(bundle).find(
+                    (output) => output.type === 'asset' && output.fileName.endsWith('.html'),
+                );
+
+            if (!entryHtmlAsset || entryHtmlAsset.type !== 'asset') {
+                this.error('Unable to detect generated entry HTML asset');
+            }
+
+            const tpl = /** @type {string} */ (entryHtmlAsset.source);
 
             // Create a tmp dir to allow importing & consuming the built modules,
             // before Rollup writes them to the disk
@@ -506,8 +534,7 @@ export function prerenderPlugin({ prerenderScript, renderTarget, additionalPrere
 
                 // Add generated HTML to compilation:
                 route.url == '/'
-                    ? (/** @type {OutputAsset} */ (bundle['index.html']).source =
-                          htmlDoc.toString())
+                    ? (entryHtmlAsset.source = htmlDoc.toString())
                     : this.emitFile({
                           type: 'asset',
                           fileName: assetName,

tests/fixtures/nested-entry/src/dashboard/index.html

@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8" />
+    </head>
+    <body>
+        <script prerender type="module" src="./main.js"></script>
+    </body>
+</html>

tests/fixtures/nested-entry/src/dashboard/main.js

@@ -0,0 +1,3 @@
+export async function prerender() {
+    return `<h1>Nested Entry Test Result</h1>`;
+}

tests/fixtures/nested-entry/vite.config.js

@@ -0,0 +1,17 @@
+import { defineConfig } from 'vite';
+import path from 'node:path';
+import url from 'node:url';
+import { vitePrerenderPlugin } from 'vite-prerender-plugin';
+
+const __dirname = path.dirname(url.fileURLToPath(import.meta.url));
+
+export default defineConfig({
+    build: {
+        rollupOptions: {
+            input: {
+                dashboard: path.resolve(__dirname, 'src/dashboard/index.html'),
+            },
+        },
+    },
+    plugins: [vitePrerenderPlugin()],
+});

tests/index.test.js

@@ -37,6 +37,14 @@ test('Should merge preload and entry chunks', async () => {
     assert.equal((await fs.readdir(outDirAssets)).length, 1);
 });
 
+test('Should support nested HTML entrypoints', async () => {
+    await loadFixture('nested-entry', env);
+    await viteBuild(env.tmp.path);
+
+    const prerenderedHtml = await getOutputFile(env.tmp.path, 'src/dashboard/index.html');
+    assert.match(prerenderedHtml, '<h1>Nested Entry Test Result</h1>');
+});
+
 test('Should bail on merging preload & entry chunks if user configures `manualChunks`', async () => {
     await loadFixture('simple', env);
     await writeConfig(env.tmp.path, `