1 files changed, 169 insertions, 0 deletions
diff --git a/docs/assets/js/index.js b/docs/assets/js/index.js
new file mode 100644
index 000000000..672d6c7a6
--- /dev/null
+++ b/docs/assets/js/index.js
@@ -0,0 +1,169 @@
+var suggestions = document.getElementById('suggestions');
+var search = document.getElementById('search');
+
+if (search !== null) {
+  document.addEventListener('keydown', inputFocus);
+}
+
+function inputFocus(e) {
+  if (e.ctrlKey && e.key === '/' ) {
+    e.preventDefault();
+    search.focus();
+  }
+  if (e.key === 'Escape' ) {
+    search.blur();
+    suggestions.classList.add('d-none');
+  }
+}
+
+document.addEventListener('click', function(event) {
+
+  var isClickInsideElement = suggestions.contains(event.target);
+
+  if (!isClickInsideElement) {
+    suggestions.classList.add('d-none');
+  }
+
+});
+
+/*
+Source:
+  - https://dev.to/shubhamprakash/trap-focus-using-javascript-6a3
+*/
+
+document.addEventListener('keydown',suggestionFocus);
+
+function suggestionFocus(e) {
+  const suggestionsHidden = suggestions.classList.contains('d-none');
+  if (suggestionsHidden) return;
+
+  const focusableSuggestions= [...suggestions.querySelectorAll('a')];
+  if (focusableSuggestions.length === 0) return;
+
+  const index = focusableSuggestions.indexOf(document.activeElement);
+
+  if (e.key === "ArrowUp") {
+    e.preventDefault();
+    const nextIndex = index > 0 ? index - 1 : 0;
+    focusableSuggestions[nextIndex].focus();
+  }
+  else if (e.key === "ArrowDown") {
+    e.preventDefault();
+    const nextIndex= index + 1 < focusableSuggestions.length ? index + 1 : index;
+    focusableSuggestions[nextIndex].focus();
+  }
+
+}
+
+/*
+Source:
+  - https://github.com/nextapps-de/flexsearch#index-documents-field-search
+  - https://raw.githack.com/nextapps-de/flexsearch/master/demo/autocomplete.html
+*/
+
+(function(){
+
+  var index = new FlexSearch.Document({
+    tokenize: "forward",
+    cache: 100,
+    document: {
+      id: 'id',
+      store: [
+        "href", "title", "description"
+      ],
+      index: ["title", "description", "content"]
+    }
+  });
+
+
+  // Not yet supported: https://github.com/nextapps-de/flexsearch#complex-documents
+
+  /*
+  var docs = [
+    {{ range $index, $page := (where .Site.Pages "Section" "docs") -}}
+      {
+        id: {{ $index }},
+        href: "{{ .Permalink }}",
+        title: {{ .Title | jsonify }},
+        description: {{ .Params.description | jsonify }},
+        content: {{ .Content | jsonify }}
+      },
+    {{ end -}}
+  ];
+  */
+
+  // https://discourse.gohugo.io/t/range-length-or-last-element/3803/2
+
+  {{ $list := (where .Site.RegularPages "Type" "in" (union .Site.Params.Sections.Search .Site.Params.Sections.Searchable)) -}}
+  {{ $len := (len $list) -}}
+
+  index.add(
+    {{ range $index, $element := $list -}}
+      {
+        id: {{ $index }},
+        href: "{{ .RelPermalink }}",
+        title: {{ .Title | jsonify }},
+        {{ with .Description -}}
+          description: {{ . | jsonify }},
+        {{ else -}}
+          description: {{ .Summary | plainify | jsonify }},
+        {{ end -}}
+        content: {{ .Plain | jsonify }}
+      })
+      {{ if ne (add $index 1) $len -}}
+        .add(
+      {{ end -}}
+    {{ end -}}
+  ;
+
+  search.addEventListener('input', show_results, true);
+
+  function show_results(){
+    const maxResult = 5;
+    var searchQuery = this.value;
+    var results = index.search(searchQuery, {limit: maxResult, enrich: true});
+
+    // flatten results since index.search() returns results for each indexed field
+    const flatResults = new Map(); // keyed by href to dedupe results
+    for (const result of results.flatMap(r => r.result)) {
+      if (flatResults.has(result.doc.href)) continue;
+      flatResults.set(result.doc.href, result.doc);
+    }
+
+    suggestions.innerHTML = "";
+    suggestions.classList.remove('d-none');
+
+    // inform user that no results were found
+    if (flatResults.size === 0 && searchQuery) {
+      const noResultsMessage = document.createElement('div')
+      noResultsMessage.innerHTML = `No results for "<strong>${searchQuery}</strong>"`
+      noResultsMessage.classList.add("suggestion__no-results");
+      suggestions.appendChild(noResultsMessage);
+      return;
+    }
+
+    // construct a list of suggestions
+    for(const [href, doc] of flatResults) {
+        const entry = document.createElement('div');
+        suggestions.appendChild(entry);
+
+        const a = document.createElement('a');
+        a.href = href;
+        entry.appendChild(a);
+
+        const title = document.createElement('span');
+        title.textContent = doc.title;
+        title.classList.add("suggestion__title");
+        a.appendChild(title);
+
+        const description = document.createElement('span');
+        description.textContent = doc.description;
+        description.classList.add("suggestion__description");
+        a.appendChild(description);
+
+        suggestions.appendChild(entry);
+
+        if(suggestions.childElementCount == maxResult) break;
+    }
+  }
+}());