🏗️🚀：minify the script the site serves

The counter shipped as it is written upstream, comments and all. It is
squeezed on the way out instead: 9,213 bytes to 5,774, and 3,327 to
2,263 once gzipped, which is the figure that counts.

The copy in the repository is untouched, which is what lets both things
be true at once: a reader downloads the small one, and the one here
stays byte for byte what upstream serves, so `nps verify.vendored` can
still tell whether it has fallen behind.

A minifier drops comments, and the two lines this one opens with are
its terms rather than decoration -- ISC asks for the notice in every
copy. They are kept, along with anything marked `@license` or
`@preserve`.

Images and scripts are both copied rather than rendered, so neither
meets a transform; the pass over the output now knows what to do with
each. That leaves nothing served here that is not squeezed: markup,
styles, marks and now this.

Signed-off-by: Derek Lewis <DerekNonGeneric@inf.is>
Assisted-by: Claude-Code:claude-opus-5
PR-URL: #1867
Fixes: #1548

Author: DerekNonGeneric

eleventy.config.mjs

@@ -1,6 +1,6 @@
 import { execFileSync } from 'node:child_process';
 import { readdir, readFile, writeFile } from 'node:fs/promises';
-import { join, parse as pathParse } from 'node:path';
+import { extname, join, parse as pathParse } from 'node:path';
 import { EleventyI18nPlugin } from '@11ty/eleventy';
 import { PATHS } from '@openinf/portal/build/constants';
 import { hasViewBox, replaceInlineSvg } from '@openinf/portal/build/inline-svg';
@@ -13,6 +13,7 @@ import markdownItGitHubAlerts from 'markdown-it-github-alerts';
 import postcss from 'postcss';
 import { compileString } from 'sass';
 import { optimize as optimizeSvg } from 'svgo';
+import { minify as minifyJs } from 'terser';
 
 // skipcq: JS-0116
 export default async function (eleventyConfig) {
@@ -221,21 +222,48 @@ export default async function (eleventyConfig) {
       return replaceInlineSvg(content, (svg) => shrinkSvg(svg, inline));
     });
 
-    // Images are copied rather than rendered, so no transform reaches them.
+    // What a script says about its own license has to reach whoever receives
+    // it. The vendored counter is ISC, which asks for the notice in every
+    // copy, and a minifier drops comments unless told which ones are not
+    // decoration.
+    const License = /@license|@preserve|ISC license|GoatCounter:/;
+
+    /**
+     * Minifies a script, keeping whatever states its terms.
+     * @param {string} code The script.
+     * @returns {Promise<string>} The minified script.
+     */
+    const shrinkJs = async (code) => {
+      const { code: minified } = await minifyJs(code, {
+        format: { comments: (_node, comment) => License.test(comment.value) },
+      });
+
+      return minified ?? code;
+    };
+
+    /** What is squeezed on the way out, and how. */
+    const squeezers = {
+      '.svg': shrinkSvg,
+      '.js': shrinkJs,
+    };
+
+    // Assets are copied rather than rendered, so no transform reaches them.
     eleventyConfig.on('eleventy.after', async ({ dir }) => {
       const entries = await readdir(dir.output, {
         recursive: true,
         withFileTypes: true,
       });
 
       await Promise.all(
-        entries
-          .filter((entry) => entry.isFile() && entry.name.endsWith('.svg'))
-          .map(async (entry) => {
-            const file = join(entry.parentPath, entry.name);
+        entries.map(async (entry) => {
+          const squeeze = squeezers[extname(entry.name)];
+
+          if (!entry.isFile() || squeeze === undefined) return;
+
+          const file = join(entry.parentPath, entry.name);
 
-            await writeFile(file, shrinkSvg(await readFile(file, 'utf8')));
-          })
+          await writeFile(file, await squeeze(await readFile(file, 'utf8')));
+        })
       );
     });
 

package.json

@@ -91,6 +91,7 @@
     "stylelint-config-recess-order": "7.8.0",
     "stylelint-config-standard-scss": "17.0.0",
     "svgo": "4.0.2",
+    "terser": "5.50.0",
     "typescript": "7.0.2",
     "unified": "11.0.5",
     "vnu-jar": "26.8.15",