feat: contextual backlinks (closes #106)

.github/workflows/deploy.yaml

@@ -14,7 +14,7 @@ jobs:
           fetch-depth: 0    # Fetch all history for .GitInfo and .Lastmod
 
       - name: Build Link Index
-        uses: jackyzha0/hugo-obsidian@v2.12
+        uses: jackyzha0/hugo-obsidian@v2.13
         with:
           index: true
           input: content

assets/js/popover.js

@@ -5,14 +5,31 @@ function htmlToElement(html) {
   return template.content.firstChild
 }
 
-function initPopover(baseURL) {
+function initPopover(baseURL, useContextualBacklinks) {
   const basePath = baseURL.replace(window.location.origin, "")
   document.addEventListener("DOMContentLoaded", () => {
     fetchData.then(({ content }) => {
       const links = [...document.getElementsByClassName("internal-link")]
       links
-        .filter(li => li.dataset.src)
+        .filter(li => li.dataset.src || (li.dataset.idx && useContextualBacklinks))
         .forEach(li => {
+          if (li.dataset.ctx) {
+            console.log(li.dataset.ctx)
+            const linkDest = content[li.dataset.src]
+            const popoverElement = `<div class="popover">
+    <h3>${linkDest.title}</h3>
+    <p>${highlight(removeMarkdown(linkDest.content), li.dataset.ctx)}...</p>
+    <p class="meta">${new Date(linkDest.lastmodified).toLocaleDateString()}</p>
+</div>`
+            const el = htmlToElement(popoverElement)
+            li.appendChild(el)
+            li.addEventListener("mouseover", () => {
+              el.classList.add("visible")
+            })
+            li.addEventListener("mouseout", () => {
+              el.classList.remove("visible")
+            })
+          } else {
             const linkDest = content[li.dataset.src.replace(/\/$/g, "").replace(basePath, "")]
             if (linkDest) {
               const popoverElement = `<div class="popover">
@@ -29,6 +46,7 @@ function initPopover(baseURL) {
                 el.classList.remove("visible")
               })
             }
+          }
         })
     })
   })

assets/js/search.js

@@ -52,40 +52,21 @@ const removeMarkdown = (
     return markdown
   }
   return output
-};
-// -----
-
-(async function() {
-  const encoder = (str) => str.toLowerCase().split(/([^a-z]|[^\x00-\x7F])+/)
-  const contentIndex = new FlexSearch.Document({
-    cache: true,
-    charset: 'latin:extra',
-    optimize: true,
-    index: [
-      {
-        field: 'content',
-        tokenize: 'reverse',
-        encode: encoder,
-      },
-      {
-        field: 'title',
-        tokenize: 'forward',
-        encode: encoder,
-      },
-    ],
-  })
-
-  const { content } = await fetchData
-  for (const [key, value] of Object.entries(content)) {
-    contentIndex.add({
-      id: key,
-      title: value.title,
-      content: removeMarkdown(value.content),
-    })
 }
+// -----
 
 const highlight = (content, term) => {
   const highlightWindow = 20
+
+  // try to find direct match first
+  const directMatchIdx = content.indexOf(term)
+  if (directMatchIdx !== -1) {
+    const h = highlightWindow / 2
+    const before = content.substring(0, directMatchIdx).split(" ").slice(-h)
+    const after = content.substring(directMatchIdx + term.length, content.length - 1).split(" ").slice(0, h)
+    return (before.length == h ? `...${before.join(" ")}` : before.join(" ")) + `<span class="search-highlight">${term}</span>` + after.join(" ")
+  }
+
   const tokenizedTerm = term.split(/\s+/).filter((t) => t !== '')
   const splitText = content.split(/\s+/).filter((t) => t !== '')
   const includesCheck = (token) =>
@@ -128,6 +109,35 @@ const removeMarkdown = (
     .replaceAll('</span> <span class="search-highlight">', ' ')
   return `${startIndex === 0 ? '' : '...'}${mappedText}${endIndex === splitText.length ? '' : '...'
     }`
+};
+
+(async function() {
+  const encoder = (str) => str.toLowerCase().split(/([^a-z]|[^\x00-\x7F])+/)
+  const contentIndex = new FlexSearch.Document({
+    cache: true,
+    charset: 'latin:extra',
+    optimize: true,
+    index: [
+      {
+        field: 'content',
+        tokenize: 'reverse',
+        encode: encoder,
+      },
+      {
+        field: 'title',
+        tokenize: 'forward',
+        encode: encoder,
+      },
+    ],
+  })
+
+  const { content } = await fetchData
+  for (const [key, value] of Object.entries(content)) {
+    contentIndex.add({
+      id: key,
+      title: value.title,
+      content: removeMarkdown(value.content),
+    })
   }
 
   const resultToHTML = ({ url, title, content, term }) => {

assets/styles/base.scss

@@ -478,16 +478,16 @@ header {
         & > h3, & > p {
           margin: 0;
         }
+      }
+    }
+  }
+}
 
-        & .search-highlight {
+.search-highlight {
   background-color: #afbfc966;
   padding: 0.05em 0.2em;
   border-radius: 3px;
 }
-      }
-    }
-  }
-}
 
 .section-ul {
   list-style: none;

data/config.yaml

@@ -4,6 +4,7 @@ openToc: false
 enableLinkPreview: true
 enableLatex: true
 enableSPA: false
+enableContextualBacklinks: true
 description:
   Host your second brain and digital garden for free. Quartz features extremely fast full-text search,
   Wikilink support, backlinks, local graph, tags, and link previews.

layouts/partials/backlinks.html

@@ -7,13 +7,18 @@
     {{$inbound := index $linkIndex.index.backlinks $curPage}}
     {{$contentTable := getJSON "/assets/indices/contentIndex.json"}}
     {{if $inbound}}
-    {{$cleanedInbound := apply (apply $inbound "index" "." "source") "replace" "." " " "-"}}
-    {{- range $cleanedInbound | uniq -}}
-      {{$l := printf "%s%s/" $host .}}
+    {{$backlinks := dict "SENTINEL" "SENTINEL"}}
+    {{range $k, $v := $inbound}}
+      {{$cleanedInbound := replace $v.source " " "-"}}
+      {{$ctx := $v.text}}
+      {{$backlinks = merge $backlinks (dict $cleanedInbound $ctx)}}
+    {{end}}
+    {{- range $lnk, $ctx := $backlinks -}}
+      {{$l := printf "%s%s/" $host $lnk}}
       {{$l = cond (eq $l "//") "/" $l}}
-      {{with (index $contentTable .)}}
+      {{with (index $contentTable $lnk)}}
       <li>
-          <a href="{{$l}}">{{index (index . "title")}}</a>
+        <a href="{{$l}}" data-ctx="{{$ctx}}" data-src="{{$lnk}}" class="internal-link">{{index (index . "title")}}</a>
       </li>
       {{end}}
     {{- end -}}

layouts/partials/popover.html

@@ -2,6 +2,7 @@
 {{ $js := resources.Get "js/popover.js" |  resources.Fingerprint "md5" | resources.Minify }}
 <script src="{{ $js.Permalink }}"></script>
 <script>
-  initPopover({{strings.TrimRight "/" .Site.BaseURL }})
+  const useContextual = {{ $.Site.Data.config.enableContextualBacklinks }}
+  initPopover({{strings.TrimRight "/" .Site.BaseURL }}, useContextual)
 </script>
 {{end}}