From 539611a05f9a6e71b1520293be6d004c3697955d Mon Sep 17 00:00:00 2001
From: Anton Bulakh <him@necauq.ua>
Date: Tue, 24 Dec 2024 02:03:09 +0200
Subject: [PATCH] feat: PageProperties component to show frontmatter similar to
 Obsidian

---
 quartz/components/PageProperties.tsx         | 165 +++++++++++++++++++
 quartz/components/index.ts                   |   2 +
 quartz/components/styles/pageProperties.scss |  42 +++++
 quartz/plugins/transformers/frontmatter.ts   |   3 +
 quartz/plugins/transformers/links.ts         |   2 +-
 5 files changed, 213 insertions(+), 1 deletion(-)
 create mode 100644 quartz/components/PageProperties.tsx
 create mode 100644 quartz/components/styles/pageProperties.scss

diff --git a/quartz/components/PageProperties.tsx b/quartz/components/PageProperties.tsx
new file mode 100644
index 000000000..523e48437
--- /dev/null
+++ b/quartz/components/PageProperties.tsx
@@ -0,0 +1,165 @@
+import { QuartzComponent, QuartzComponentConstructor, QuartzComponentProps } from "./types"
+import { classNames } from "../util/lang"
+import { ComponentChildren, ComponentType } from "preact"
+import { externalLinkRegex, wikilinkRegex } from "../plugins/transformers/ofm"
+import style from "./styles/pageProperties.scss"
+import { pathToRoot, simplifySlug, slugTag, transformLink } from "../util/path"
+import { getFullInternalLink } from "../plugins/transformers/links"
+
+export type FieldComponent = ComponentType<
+  QuartzComponentProps & { fieldName: string; fieldValue: any }
+>
+
+interface PagePropertiesOptions {
+  fieldComponents: {
+    [name: string]: FieldComponent
+  }
+  defaultFieldComponent: FieldComponent
+}
+
+// this is ugly, we kind of ripped out what quartz does from ofm.ts
+// at least in my earlier commit we separated out the `getFullInternalLink` part
+// also hardcoded "shortest" transform strategy
+function renderInternalLink(
+  value: string,
+  rawFp: string,
+  rawHeader: string | undefined,
+  rawAlias: string | undefined,
+  props: QuartzComponentProps,
+): ComponentChildren {
+  const fp = rawFp?.trim() ?? ""
+  const anchor = rawHeader?.trim() ?? ""
+  const alias = rawAlias?.slice(1).trim()
+
+  const url = fp + anchor
+  const text = alias ?? fp
+
+  const href = transformLink(props.fileData.slug!, url, {
+    strategy: "shortest",
+    allSlugs: props.ctx.allSlugs,
+  })
+  const full = getFullInternalLink(href, simplifySlug(props.fileData.slug!))
+
+  return (
+    <a class="internal" href={href} data-slug={full}>
+      {text}
+    </a>
+  )
+}
+
+export const DefaultFieldComponent: FieldComponent = (props) => {
+  const { fieldValue } = props
+  if (fieldValue === null) {
+    return "null"
+  }
+  if (fieldValue === undefined) {
+    return null
+  }
+  if (typeof fieldValue === "string") {
+    if (fieldValue.match(externalLinkRegex)) {
+      return (
+        <a class="external" href={fieldValue} target="_blank">
+          {fieldValue}
+        </a>
+      )
+    }
+    const [match] = [...fieldValue.matchAll(wikilinkRegex)]
+    if (match && match[0] === fieldValue && !fieldValue.startsWith("!")) {
+      return renderInternalLink(fieldValue, match[1], match[2], match[3], props)
+    }
+    return fieldValue
+  }
+  if (Array.isArray(fieldValue)) {
+    if (fieldValue.length === 0) {
+      return null
+    }
+    return (
+      <ul class="property-list">
+        {fieldValue.map((v) => (
+          <li>
+            <DefaultFieldComponent {...props} fieldValue={v} />
+          </li>
+        ))}
+      </ul>
+    )
+  }
+  if (typeof fieldValue === "object") {
+    return <code>{JSON.stringify(fieldValue, null, 2)}</code>
+  }
+  return fieldValue.toString?.() ?? null
+}
+
+export const TagFieldComponent: FieldComponent = ({ fieldValue, fileData }) => {
+  const tags = Array.isArray(fieldValue) ? fieldValue : [fieldValue]
+  const baseDir = pathToRoot(fileData.slug!)
+  return (
+    <ul class="property-list">
+      {tags.map((tag) => {
+        return (
+          <li>
+            <a href={`${baseDir}/tags/${slugTag(`${tag}`)}`} class="internal tag-link">
+              {tag}
+            </a>
+          </li>
+        )
+      })}
+    </ul>
+  )
+}
+
+// A sentinel value that hides a field
+export const HIDE = () => null
+
+const defaultOptions: PagePropertiesOptions = {
+  fieldComponents: {
+    title: HIDE,
+    date: HIDE,
+    cssclasses: HIDE,
+    tags: TagFieldComponent,
+    ["hide-props"]: HIDE,
+  },
+  defaultFieldComponent: DefaultFieldComponent,
+}
+
+export default ((opts?: Partial<PagePropertiesOptions>) => {
+  const fieldComponents = { ...defaultOptions.fieldComponents, ...opts?.fieldComponents }
+  const DefaultFieldComponent = opts?.defaultFieldComponent ?? defaultOptions.defaultFieldComponent
+
+  const PageProperties: QuartzComponent = (props: QuartzComponentProps) => {
+    if (!props.fileData.frontmatterRaw) {
+      return null
+    }
+
+    const hideRaw = props.fileData.frontmatter?.["hide-props"] ?? []
+    const hide = Array.isArray(hideRaw) ? hideRaw : [hideRaw]
+
+    const entries = Object.entries(props.fileData.frontmatterRaw).map(([name, value]) => {
+      // allow hiding through frontmatter
+      if (hide.includes(name)) {
+        return null
+      }
+      const FieldComponent = fieldComponents[name] ?? DefaultFieldComponent
+      // allow hiding through config
+      if (FieldComponent === HIDE) {
+        return null
+      }
+      return (
+        <>
+          <dt>{name}</dt>
+          <dd>
+            <FieldComponent {...props} fieldName={name} fieldValue={value} />
+          </dd>
+        </>
+      )
+    })
+
+    // avoid the padding if there's no frontmatter
+    return entries.length !== 0 ? (
+      <dl class={classNames(props.displayClass, "page-props")}>{entries}</dl>
+    ) : null
+  }
+
+  PageProperties.css = style
+
+  return PageProperties
+}) satisfies QuartzComponentConstructor
diff --git a/quartz/components/index.ts b/quartz/components/index.ts
index 5b197941c..d64fc61ce 100644
--- a/quartz/components/index.ts
+++ b/quartz/components/index.ts
@@ -11,6 +11,7 @@ import Spacer from "./Spacer"
 import TableOfContents from "./TableOfContents"
 import Explorer from "./Explorer"
 import TagList from "./TagList"
+import PageProperties from "./PageProperties"
 import Graph from "./Graph"
 import Backlinks from "./Backlinks"
 import Search from "./Search"
@@ -34,6 +35,7 @@ export {
   TableOfContents,
   Explorer,
   TagList,
+  PageProperties,
   Graph,
   Backlinks,
   Search,
diff --git a/quartz/components/styles/pageProperties.scss b/quartz/components/styles/pageProperties.scss
new file mode 100644
index 000000000..820e03300
--- /dev/null
+++ b/quartz/components/styles/pageProperties.scss
@@ -0,0 +1,42 @@
+.page-props {
+  display: grid;
+  gap: 4px 16px;
+  grid-template-columns: max-content;
+  color: var(--darkgray);
+
+  > dt {
+    font-weight: bold;
+    font-family: mono;
+    font-size: 0.8em;
+    align-self: center;
+  }
+
+  > dd {
+    margin: 0;
+    grid-column-start: 2;
+  }
+
+  .internal {
+    padding: 0 0.25rem;
+  }
+
+  .property-list {
+    list-style: none;
+    padding: 0;
+    margin: 0;
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.2rem;
+
+    > li {
+      line-height: initial;
+      display: flex;
+    }
+
+    > li:not(:last-child) {
+      &::after {
+        content: ",";
+      }
+    }
+  }
+}
diff --git a/quartz/plugins/transformers/frontmatter.ts b/quartz/plugins/transformers/frontmatter.ts
index e00c700e0..63fdf56df 100644
--- a/quartz/plugins/transformers/frontmatter.ts
+++ b/quartz/plugins/transformers/frontmatter.ts
@@ -57,6 +57,8 @@ export const FrontMatter: QuartzTransformerPlugin<Partial<Options>> = (userOpts)
               },
             })
 
+            ;(file.data as any).frontmatterRaw = structuredClone(data)
+
             if (data.title != null && data.title.toString() !== "") {
               data.title = data.title.toString()
             } else {
@@ -115,5 +117,6 @@ declare module "vfile" {
         socialImage: string
         comments: boolean | string
       }>
+    readonly frontmatterRaw: { readonly [key: string]: Readonly<any> }
   }
 }
diff --git a/quartz/plugins/transformers/links.ts b/quartz/plugins/transformers/links.ts
index 88d1b93d8..28f975457 100644
--- a/quartz/plugins/transformers/links.ts
+++ b/quartz/plugins/transformers/links.ts
@@ -35,7 +35,7 @@ const defaultOptions: Options = {
   indexFrontmatterWikilinks: false,
 }
 
-function getFullInternalLink(dest: RelativeURL, fileSlug: SimpleSlug): FullSlug {
+export function getFullInternalLink(dest: RelativeURL, fileSlug: SimpleSlug): FullSlug {
   // url.resolve is considered legacy
   // WHATWG equivalent https://nodejs.dev/en/api/v18/url/#urlresolvefrom-to
   const url = new URL(dest, "https://base.com/" + stripSlashes(fileSlug, true))