feat: comments (giscus)

docs/features/comments.md

@@ -0,0 +1,83 @@
+---
+title: Comments
+tags:
+  - component
+---
+
+Quartz also has the ability to hook into various providers to enable readers to leave comments on your site.
+
+![[giscus-example.png]]
+
+As of today, only [Giscus](https://giscus.app/) is supported out of the box but PRs to support other providers are welcome!
+
+## Providers
+
+### Giscus
+
+First, make sure that the [[setting up your GitHub repository|GitHub]] repository you are using for your Quartz meets the following requirements:
+
+1. The **repository is [public](https://docs.github.com/en/github/administering-a-repository/managing-repository-settings/setting-repository-visibility#making-a-repository-public)**, otherwise visitors will not be able to view the discussion.
+2. The **[giscus](https://github.com/apps/giscus) app is installed**, otherwise visitors will not be able to comment and react.
+3. The **Discussions feature is turned on** by [enabling it for your repository](https://docs.github.com/en/github/administering-a-repository/managing-repository-settings/enabling-or-disabling-github-discussions-for-a-repository).
+
+Then, use the [Giscus site](https://giscus.app/#repository) to figure out what your `repoId` and `categoryId` should be. Make sure you select `Announcements` for the Discussion category.
+
+![[giscus-repo.png]]
+
+![[giscus-discussion.png]]
+
+After entering both your repository and selecting the discussion category, Giscus will compute some IDs that you'll need to provide back to Quartz. You won't need to manually add the script yourself as Quartz will handle that part for you but will need these values in the next step!
+
+![[giscus-results.png]]
+
+Finally, in `quartz.layout.ts`, edit the `afterBody` field of `sharedPageComponents` to include the following options but with the values you got from above:
+
+```ts title="quartz.layout.ts"
+afterBody: [
+  Component.Comments({
+    provider: 'giscus',
+    options: {
+      // from data-repo
+      repo: 'jackyzha0/quartz',
+      // from data-repo-id
+      repoId: 'MDEwOlJlcG9zaXRvcnkzODcyMTMyMDg',
+      // from data-category
+      category: 'Announcements',
+      // from data-category-id
+      categoryId: 'DIC_kwDOFxRnmM4B-Xg6',
+    }
+  }),
+],
+```
+
+### Customization
+
+Quartz also exposes a few of the other Giscus options as well and you can provide them the same way `repo`, `repoId`, `category`, and `categoryId` are provided.
+
+```ts
+type Options = {
+  provider: "giscus"
+  options: {
+    repo: `${string}/${string}`
+    repoId: string
+    category: string
+    categoryId: string
+
+    // how to map pages -> discussions
+    // defaults to 'url'
+    mapping?: "url" | "title" | "og:title" | "specific" | "number" | "pathname"
+
+    // use strict title matching
+    // defaults to true
+    strict?: boolean
+
+    // whether to enable reactions for the main post
+    // defaults to true
+    reactionsEnabled?: boolean
+
+    // where to put the comment input box relative to the comments
+    // defaults to 'bottom'
+    inputPosition?: "top" | "bottom"
+  }
+}
+```

docs/index.md

@@ -31,7 +31,7 @@ If you prefer instructions in a video format you can try following Nicole van de
 
 ## 🔧 Features
 
-- [[Obsidian compatibility]], [[full-text search]], [[graph view]], note transclusion, [[wikilinks]], [[backlinks]], [[features/Latex|Latex]], [[syntax highlighting]], [[popover previews]], [[Docker Support]], [[i18n|internationalization]] and [many more](./features) right out of the box
+- [[Obsidian compatibility]], [[full-text search]], [[graph view]], note transclusion, [[wikilinks]], [[backlinks]], [[features/Latex|Latex]], [[syntax highlighting]], [[popover previews]], [[Docker Support]], [[i18n|internationalization]], [[comments]] and [many more](./features) right out of the box
 - Hot-reload for both configuration and content
 - Simple JSX layouts and [[creating components|page components]]
 - [[SPA Routing|Ridiculously fast page loads]] and tiny bundle sizes

quartz/components/Comments.tsx

@@ -0,0 +1,66 @@
+import { QuartzComponent, QuartzComponentConstructor, QuartzComponentProps } from "./types"
+
+type Options = {
+  provider: "giscus"
+  options: {
+    repo: `${string}/${string}`
+    repoId: string
+    category: string
+    categoryId: string
+    mapping?: "url" | "title" | "og:title" | "specific" | "number" | "pathname"
+    strict?: boolean
+    reactionsEnabled?: boolean
+    inputPosition?: "top" | "bottom"
+  }
+}
+
+function boolToStringBool(b: boolean): string {
+  return b ? "1" : "0"
+}
+
+export default ((opts: Options) => {
+  const Comments: QuartzComponent = (_props: QuartzComponentProps) => <div class="giscus"></div>
+  Comments.afterDOMLoaded = `
+      const giscusScript = document.createElement("script")
+      giscusScript.src = "https://giscus.app/client.js"
+      giscusScript.async = true
+      giscusScript.crossOrigin = "anonymous"
+      giscusScript.setAttribute("data-loading", "lazy")
+      giscusScript.setAttribute("data-emit-metadata", "0")
+      giscusScript.setAttribute("data-repo", "${opts.options.repo}")
+      giscusScript.setAttribute("data-repo-id", "${opts.options.repoId}")
+      giscusScript.setAttribute("data-category", "${opts.options.category}")
+      giscusScript.setAttribute("data-category-id", "${opts.options.categoryId}")
+      giscusScript.setAttribute("data-mapping", "${opts.options.mapping ?? "url"}")
+      giscusScript.setAttribute("data-strict", "${boolToStringBool(opts.options.strict ?? true)}")
+      giscusScript.setAttribute("data-reactions-enabled", "${boolToStringBool(opts.options.reactionsEnabled ?? true)}")
+      giscusScript.setAttribute("data-input-position", "${opts.options.inputPosition ?? "bottom"}")
+
+      const theme = document.documentElement.getAttribute("saved-theme")
+      giscusScript.setAttribute("data-theme", theme)
+      document.head.appendChild(giscusScript)
+
+      const changeTheme = (e) => {
+        const theme = e.detail.theme
+        const iframe = document.querySelector('iframe.giscus-frame')
+        if (!iframe) {
+          return
+        }
+
+        iframe.contentWindow.postMessage({
+          giscus: {
+            setConfig: {
+              theme: theme
+            }
+          }
+        }, 'https://giscus.app')
+      }
+
+      document.addEventListener("nav", () => {
+        document.addEventListener("themechange", changeTheme)
+        window.addCleanup(() => document.removeEventListener("themechange", changeTheme))
+      })
+  `
+
+  return Comments
+}) satisfies QuartzComponentConstructor<Options>

quartz/components/index.ts

@@ -19,6 +19,7 @@ import DesktopOnly from "./DesktopOnly"
 import MobileOnly from "./MobileOnly"
 import RecentNotes from "./RecentNotes"
 import Breadcrumbs from "./Breadcrumbs"
+import Comments from "./Comments"
 
 export {
   ArticleTitle,
@@ -42,4 +43,5 @@ export {
   RecentNotes,
   NotFound,
   Breadcrumbs,
+  Comments,
 }