Update search.js

搜索结果中标出搜索词；上下键在结果间移动、回车打开、Esc 先取消选中再清空，⌘K / Ctrl+K 聚焦搜索框；打开结果后在目标小节中标出搜索词。

website/templates/search.js

@@ -77,21 +77,37 @@
     });
   }
 
-  function snippet(text, query) {
-    var first = normalize(query).split(' ')[0];
-    var position = normalize(text).indexOf(first);
+  function snippet(text, terms) {
+    var lower = normalize(text), position = -1;
+    // 先找最长的词：“死锁的四个条件”的摘要应定位到“四个条件”，而不是第一次出现“死锁”的地方
+    (Array.isArray(terms) ? terms.slice() : normalize(terms).split(' ')).sort(function (a, b) { return b.length - a.length; })
+      .some(function (term) { position = term ? lower.indexOf(term) : -1; return position !== -1; });
     var start = Math.max(0, position - 45);
     return (start ? '…' : '') + text.slice(start, start + 170) + (text.length > start + 170 ? '…' : '');
   }
 
+  // 摘要和标题中标出搜索词：先按搜索词切分原文再逐段转义，不会匹配到转义后的实体
+  function highlight(text, query) {
+    var terms = (Array.isArray(query) ? query : normalize(query).split(' ')).filter(Boolean).sort(function (a, b) { return b.length - a.length; }).map(function (term) {
+      return term.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+    });
+    if (!terms.length) return escapeHtml(text);
+    var pattern = new RegExp('(' + terms.join('|') + ')', 'gi');
+    return String(text).split(pattern).map(function (part, index) {
+      return index % 2 ? '<mark>' + escapeHtml(part) + '</mark>' : escapeHtml(part);
+    }).join('');
+  }
+
   function mountSearch() {
     var sidebar = document.querySelector('.sidebar');
     if (!sidebar || sidebar.querySelector('.site-search')) return;
     var wrapper = document.createElement('div');
     wrapper.className = 'search site-search';
-    wrapper.innerHTML = '<input type="search" aria-label="搜索全部笔记" aria-controls="site-search-results" placeholder="搜索全部笔记" autocomplete="off">' +
+    var mac = /Mac|iPhone|iPad/.test(navigator.platform || navigator.userAgent);
+    wrapper.innerHTML = '<input type="search" role="combobox" aria-expanded="false" aria-autocomplete="list" aria-label="搜索全部笔记" aria-controls="site-search-results" placeholder="搜索全部笔记" autocomplete="off" enterkeyhint="search">' +
+      '<kbd class="search-key" aria-hidden="true">' + (mac ? '⌘K' : 'Ctrl K') + '</kbd>' +
       '<p class="search-status" role="status" aria-live="polite"></p>' +
-      '<div id="site-search-results" class="results-panel" hidden></div>';
+      '<div id="site-search-results" class="results-panel" role="listbox" aria-label="搜索结果" hidden></div>';
     sidebar.insertBefore(wrapper, sidebar.firstChild);
     var input = wrapper.querySelector('input');
     var status = wrapper.querySelector('.search-status');
@@ -104,40 +120,153 @@
       var request = ++sequence;
       panel.hidden = !query;
       panel.innerHTML = '';
+      input.setAttribute('aria-expanded', String(!!query));
+      setActive(-1);
       if (!query) { status.textContent = ''; return; }
       status.textContent = '正在搜索…';
       loadIndex().then(function (index) {
         if (request !== sequence) return;
-        var results = search(index, query);
-        status.textContent = results.length ? '找到 ' + results.length + ' 个相关章节' : '没有找到相关内容';
-        panel.innerHTML = results.map(function (result) {
+        var results = search(index, query), terms = normalize(query).split(' ').filter(Boolean);
+        status.textContent = results.length ? '找到 ' + results.length + ' 个相关章节' : '没有找到相关内容，可以换个说法或减少关键词';
+        lastTerms = terms;
+        panel.innerHTML = results.map(function (result, i) {
           var url = '/#' + result.path.split('/').map(encodeURIComponent).join('/') +
             (result.id ? '?id=' + encodeURIComponent(result.id) : '');
-          return '<a class="matching-post" href="' + escapeHtml(url) + '"><strong>' + escapeHtml(result.title) +
-            '</strong><small>' + escapeHtml(result.page) + '</small><p>' + escapeHtml(snippet(result.text, query)) + '</p></a>';
+          return '<a class="matching-post" id="search-result-' + i + '" role="option" aria-selected="false" tabindex="-1" href="' + escapeHtml(url) + '"><strong>' + highlight(result.title, terms) +
+            '</strong><small>' + escapeHtml(result.page) + '</small><p>' + highlight(snippet(result.text, terms), terms) + '</p></a>';
         }).join('');
+        markCurrent();
       }).catch(function () {
         if (request === sequence) status.textContent = '搜索暂时不可用，请稍后重试。';
       });
     }
     input.addEventListener('focus', function () { loadIndex().catch(function () {}); });
     input.addEventListener('input', function () { clearTimeout(timer); timer = setTimeout(update, 140); });
+    // 当前选中的结果：焦点一直在输入框里，可以接着修改搜索词
+    var active = -1, lastTerms = [];
+    function options() { return Array.from(panel.querySelectorAll('.matching-post')); }
+    function setActive(i) {
+      var list = options();
+      active = list.length ? Math.max(-1, Math.min(i, list.length - 1)) : -1;
+      list.forEach(function (link, j) { link.setAttribute('aria-selected', String(j === active)); });
+      if (active >= 0) {
+        input.setAttribute('aria-activedescendant', list[active].id);
+        list[active].scrollIntoView({ block: 'nearest' });
+      } else {
+        input.removeAttribute('aria-activedescendant');
+      }
+    }
     input.addEventListener('keydown', function (event) {
       if (event.isComposing || event.keyCode === 229) return;
-      if (event.key === 'Escape') { input.value = ''; update(); }
-      var first = panel.querySelector('a');
-      if (first && event.key === 'ArrowDown') { event.preventDefault(); first.focus(); }
-      if (first && event.key === 'Enter') { event.preventDefault(); first.click(); }
+      var list = options();
+      if (event.key === 'ArrowDown' || event.key === 'ArrowUp') {
+        if (!list.length) return;
+        event.preventDefault();
+        var step = event.key === 'ArrowDown' ? 1 : -1;
+        setActive(active === -1 && step < 0 ? list.length - 1 : active + step >= list.length ? 0 : active + step);
+      } else if (event.key === 'Enter') {
+        // 结果还没出来时（输入后 140ms 内）先搜一次，再打开第一条
+        if (!list.length && input.value.trim()) { clearTimeout(timer); update(); return; }
+        if (!list.length) return;
+        event.preventDefault();
+        (list[active] || list[0]).click();
+      } else if (event.key === 'Escape') {
+        event.preventDefault();
+        if (active >= 0) setActive(-1);
+        else if (input.value) { input.value = ''; update(); }
+        else input.blur();
+      }
     });
+    panel.addEventListener('mousemove', function (event) {
+      var link = event.target.closest('.matching-post');
+      if (link) { var i = options().indexOf(link); if (i !== active) setActive(i); }
+    });
+    // ⌘K / Ctrl+K 在任何地方聚焦搜索框（手机上同时打开侧边栏）
+    document.addEventListener('keydown', function (event) {
+      if (event.key !== 'k' && event.key !== 'K' || !(event.metaKey || event.ctrlKey) || event.altKey || event.shiftKey) return;
+      event.preventDefault();
+      document.body.classList.toggle('close', window.matchMedia('(max-width: 768px)').matches);
+      input.focus();
+      input.select();
+    });
+    // 搜索结果在跳转后保留，方便接着看下一条；当前所在的小节标为 aria-current
+    function markCurrent() {
+      var here = decodeURIComponent(location.hash);
+      panel.querySelectorAll('.matching-post').forEach(function (link) {
+        var same = decodeURIComponent(link.getAttribute('href').slice(1)) === here;
+        if (same) link.setAttribute('aria-current', 'location'); else link.removeAttribute('aria-current');
+      });
+    }
+    window.addEventListener('hashchange', markCurrent);
     panel.addEventListener('click', function (event) {
-      if (event.target.closest('a') && window.matchMedia('(max-width: 768px)').matches) {
+      var link = event.target.closest('a');
+      if (link) {
+        try { sessionStorage.setItem('cs-notes-search-hit', JSON.stringify({ href: link.getAttribute('href'), terms: lastTerms, time: Date.now() })); } catch (error) {}
+        setTimeout(markHits, 60);
+      }
+      if (link && window.matchMedia('(max-width: 768px)').matches) {
         document.body.classList.remove('close');
       }
     });
   }
 
+  var HIT_SKIP = /^(PRE|CODE|SCRIPT|STYLE|MARK|BUTTON|SVG)$/;
+  function clearHits() {
+    document.querySelectorAll('mark.search-hit').forEach(function (mark) {
+      mark.replaceWith(document.createTextNode(mark.textContent));
+    });
+  }
+  function markHits() {
+    var saved;
+    try { saved = JSON.parse(sessionStorage.getItem('cs-notes-search-hit')); } catch (error) { return; }
+    if (!saved || Date.now() - saved.time > 30000) return;
+    var hash = decodeURIComponent(location.hash), href = decodeURIComponent(saved.href.replace(/^\//, ''));
+    if (hash !== href) return;
+    sessionStorage.removeItem('cs-notes-search-hit');
+    clearHits();
+    var id = new URLSearchParams(href.split('?').slice(1).join('?')).get('id');
+    var heading = id && document.getElementById(id), section = document.querySelector('.markdown-section');
+    if (!section || !saved.terms || !saved.terms.length) return;
+    var level = heading && /^H([1-6])$/.test(heading.tagName) ? Number(heading.tagName[1]) : 0;
+    var nodes = [], node = heading || section.firstElementChild;
+    for (; node; node = node.nextElementSibling) {
+      if (node !== heading && /^H[1-6]$/.test(node.tagName) && Number(node.tagName[1]) <= level) break;
+      nodes.push(node);
+    }
+    var terms = saved.terms.filter(Boolean).sort(function (a, b) { return b.length - a.length; });
+    var pattern = new RegExp('(' + terms.map(function (term) { return term.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); }).join('|') + ')', 'gi');
+    var count = 0;
+    nodes.forEach(function (block) {
+      var walker = document.createTreeWalker(block, NodeFilter.SHOW_TEXT, {
+        acceptNode: function (text) {
+          for (var p = text.parentNode; p && p !== block.parentNode; p = p.parentNode) if (HIT_SKIP.test(p.nodeName.toUpperCase())) return NodeFilter.FILTER_REJECT;
+          return NodeFilter.FILTER_ACCEPT;
+        }
+      });
+      var texts = [];
+      while (walker.nextNode()) texts.push(walker.currentNode);
+      texts.forEach(function (text) {
+        var parts = text.nodeValue.split(pattern);
+        if (parts.length < 2 || count > 60) return;
+        var fragment = document.createDocumentFragment();
+        parts.forEach(function (part, i) {
+          if (!part) return;
+          if (i % 2) { var mark = document.createElement('mark'); mark.className = 'search-hit'; mark.textContent = part; fragment.appendChild(mark); count++; }
+          else fragment.appendChild(document.createTextNode(part));
+        });
+        text.replaceWith(fragment);
+      });
+    });
+    if (heading) {
+      heading.classList.remove('jump-target');
+      void heading.offsetWidth;
+      heading.classList.add('jump-target');
+    }
+  }
+
   window.$docsify.plugins.push(function (hook) {
     hook.mounted(mountSearch);
     hook.doneEach(mountSearch);
+    hook.doneEach(function () { setTimeout(markHits, 0); });
   });
 })();