refactor(v2): precompile ETA templates (#3238)

* compile ETA templates ahead of time

* handle PR review

packages/docusaurus-plugin-client-redirects/src/createRedirectPageContent.ts

@@ -7,15 +7,25 @@
 
 import * as eta from 'eta';
 import redirectPageTemplate from './templates/redirectPage.template.html';
+import {memoize} from 'lodash';
 
 type CreateRedirectPageOptions = {
   toUrl: string;
 };
 
+const getCompiledRedirectPageTemplate = memoize(() => {
+  return eta.compile(redirectPageTemplate.trim());
+});
+
+function renderRedirectPageTemplate(data: object) {
+  const compiled = getCompiledRedirectPageTemplate();
+  return compiled(data, eta.defaultConfig);
+}
+
 export default function createRedirectPageContent({
   toUrl,
 }: CreateRedirectPageOptions) {
-  return eta.render(redirectPageTemplate.trim(), {
+  return renderRedirectPageTemplate({
     toUrl: encodeURI(toUrl),
   });
 }

packages/docusaurus-theme-search-algolia/src/index.js

@@ -11,6 +11,16 @@ const eta = require('eta');
 const {normalizeUrl} = require('@docusaurus/utils');
 const openSearchTemplate = require('./templates/opensearch');
 const {validateThemeConfig} = require('./validateThemeConfig');
+const {memoize} = require('lodash');
+
+const getCompiledOpenSearchTemplate = memoize(() => {
+  return eta.compile(openSearchTemplate.trim());
+});
+
+function renderOpenSearchTemplate(data) {
+  const compiled = getCompiledOpenSearchTemplate();
+  return compiled(data, eta.defaultConfig);
+}
 
 const OPEN_SEARCH_FILENAME = 'opensearch.xml';
 
@@ -44,13 +54,14 @@ function theme(context) {
       try {
         fs.writeFileSync(
           path.join(outDir, OPEN_SEARCH_FILENAME),
-          eta.render(openSearchTemplate.trim(), {
+          renderOpenSearchTemplate({
             title,
             url,
             favicon: normalizeUrl([url, favicon]),
           }),
         );
       } catch (err) {
+        console.error(err);
         throw new Error(`Generating OpenSearch file failed: ${err}`);
       }
     },

packages/docusaurus/src/client/serverEntry.js

@@ -28,6 +28,20 @@ import {
 } from './LinksCollector';
 import ssrTemplate from './templates/ssr.html.template';
 
+// eslint-disable-next-line no-restricted-imports
+import {memoize} from 'lodash';
+
+const getCompiledSSRTemplate = memoize(() => {
+  return eta.compile(ssrTemplate.trim(), {
+    rmWhitespace: true,
+  });
+});
+
+function renderSSRTemplate(data) {
+  const compiled = getCompiledSSRTemplate();
+  return compiled(data, eta.defaultConfig);
+}
+
 // Renderer for static-site-generator-webpack-plugin (async rendering via promises).
 export default async function render(locals) {
   const {
@@ -76,9 +90,7 @@ export default async function render(locals) {
   const stylesheets = (bundles.css || []).map((b) => b.file);
   const scripts = (bundles.js || []).map((b) => b.file);
 
-  const renderedHtml = eta.render(
+  const renderedHtml = renderSSRTemplate({
-    ssrTemplate.trim(),
-    {
     appHtml,
     baseUrl,
     htmlAttributes: htmlAttributes || '',
@@ -90,12 +102,7 @@ export default async function render(locals) {
     scripts,
     stylesheets,
     version: packageJson.version,
-    },
+  });
-    {
-      name: 'ssr-template',
-      rmWhitespace: true,
-    },
-  );
 
   // Minify html with https://github.com/DanielRuf/html-minifier-terser
   return minify(renderedHtml, {