feat(backlinks): hide by default when empty (#1674)

Co-authored-by: Aaron Pham <Aaronpham0103@gmail.com>

docs/features/backlinks.md

@@ -9,6 +9,7 @@ A backlink for a note is a link from another note to that note. Links in the bac
 ## Customization
 
 - Removing backlinks: delete all usages of `Component.Backlinks()` from `quartz.layout.ts`.
+- Hide when empty: hide `Backlinks` if given page doesn't contain any backlinks (default to `true`). To disable this, use `Component.Backlinks({ hideWhenEmpty: false })`.
 - Component: `quartz/components/Backlinks.tsx`
 - Style: `quartz/components/styles/backlinks.scss`
 - Script: `quartz/components/scripts/search.inline.ts`

quartz/components/Backlinks.tsx

@@ -4,6 +4,17 @@ import { resolveRelative, simplifySlug } from "../util/path"
 import { i18n } from "../i18n"
 import { classNames } from "../util/lang"
 
+interface BacklinksOptions {
+  hideWhenEmpty: boolean
+}
+
+const defaultOptions: BacklinksOptions = {
+  hideWhenEmpty: true,
+}
+
+export default ((opts?: Partial<BacklinksOptions>) => {
+  const options: BacklinksOptions = { ...defaultOptions, ...opts }
+
   const Backlinks: QuartzComponent = ({
     fileData,
     allFiles,
@@ -12,6 +23,9 @@ const Backlinks: QuartzComponent = ({
   }: QuartzComponentProps) => {
     const slug = simplifySlug(fileData.slug!)
     const backlinkFiles = allFiles.filter((file) => file.links?.includes(slug))
+    if (options.hideWhenEmpty && backlinkFiles.length == 0) {
+      return null
+    }
     return (
       <div class={classNames(displayClass, "backlinks")}>
         <h3>{i18n(cfg.locale).components.backlinks.title}</h3>
@@ -33,4 +47,6 @@ const Backlinks: QuartzComponent = ({
   }
 
   Backlinks.css = style
-export default (() => Backlinks) satisfies QuartzComponentConstructor
+
+  return Backlinks
+}) satisfies QuartzComponentConstructor