docs: fix watch mode for JS (#9044)

* docs: fix watch mode for JS

Closes #9041

* Fix glob-watcher API usage
* generate glob list manually
* add comment

Author: alxndrsn

bin/build-site.js

@@ -17,53 +17,49 @@ const POUCHDB_LESS = resolvePath('docs/src/less/pouchdb/pouchdb.less');
 
 process.chdir('docs');
 
-function checkJekyll() {
-  return exec('bundle check').catch(function () {
+async function checkJekyll() {
+  try {
+    await exec('bundle check');
+  } catch (err) {
     throw new Error('Jekyll is not installed.  You need to do: npm run install-jekyll');
-  });
+  }
 }
 
-function buildCSS() {
+async function buildCSS() {
   fs.mkdirSync(__dirname + '/../docs/static/css', { recursive:true });
   const cmd = [ resolvePath('node_modules/less/bin/lessc'), POUCHDB_LESS ].join(' ');
-  return exec(cmd).then(function (child) {
-    var minifiedCss = cssmin(child.stdout);
-    fs.writeFileSync(POUCHDB_CSS, minifiedCss);
-    console.log('Updated: ', POUCHDB_CSS);
-  });
+  const { stdout } = await exec(cmd);
+  const minifiedCss = cssmin(stdout);
+  fs.writeFileSync(POUCHDB_CSS, minifiedCss);
+  console.log('Updated:', POUCHDB_CSS);
 }
 
-function buildJekyll(path) {
-  // Don't rebuild on website artifacts being written
-  if (path && /^_site/.test(path.relative)) {
-    return;
-  }
-  return exec('bundle exec jekyll build').then(function () {
-    console.log('=> Rebuilt jekyll');
-    return highlightEs6();
-  }).then(function () {
-    console.log('=> Highlighted ES6');
-
-    const srcPath = resolvePath('docs/src/code.js');
-    const targetPath = resolvePath('docs/_site/static/js/code.min.js');
-    const src = fs.readFileSync(srcPath, { encoding:'utf8' });
-    const mangle = { toplevel: true };
-    const output = { ascii_only: true };
-    const { code, error } = terser.minify(src, { mangle, output });
-    if (error) {
-      if (process.env.BUILD) {
-        throw error;
-      } else {
-        console.log(
-          `Javascript minification failed on line ${error.line} col ${error.col}:`,
-          error.message,
-        );
-      }
+async function buildJekyll() {
+  await exec('bundle exec jekyll build');
+  console.log('=> Rebuilt jekyll');
+
+  highlightEs6();
+  console.log('=> Highlighted ES6');
+
+  const srcPath = resolvePath('docs/src/code.js');
+  const targetPath = resolvePath('docs/_site/static/js/code.min.js');
+  const src = fs.readFileSync(srcPath, { encoding:'utf8' });
+  const mangle = { toplevel: true };
+  const output = { ascii_only: true };
+  const { code, error } = terser.minify(src, { mangle, output });
+  if (error) {
+    if (process.env.BUILD) {
+      throw error;
     } else {
-      fs.writeFileSync(targetPath, code);
-      console.log('Minified javascript.');
+      console.log(
+        `Javascript minification failed on line ${error.line} col ${error.col}:`,
+        error.message,
+      );
     }
-  });
+  } else {
+    fs.writeFileSync(targetPath, code);
+    console.log('Minified javascript.');
+  }
 }
 
 function highlightEs6() {
@@ -101,8 +97,23 @@ if (!process.env.BUILD) {
   const http_server = require('http-server');
   const watchGlob = require('glob-watcher');
 
-  watchGlob('**', buildJekyll);
+  // Simpler ways of blacklisting certain paths here would be very welcome.
+  fs.readdirSync('.')
+    .forEach(path => {
+      if (path === '_site' || path.startsWith('Gemfile')) {
+        return;
+      }
+
+      if (fs.statSync(path).isDirectory()) {
+        watchGlob(`${path}/**`, buildJekyll);
+      } else {
+        watchGlob(path, buildJekyll);
+      }
+    });
+
+
   watchGlob('static/src/*/*.less', buildCSS);
+
   http_server.createServer({root: '_site', cache: '-1'}).listen(4000);
   console.log('Server address: http://localhost:4000');
 }