Initial commit

quartz/plugins/transformers/description.ts

@@ -0,0 +1,82 @@
+import { Root as HTMLRoot } from "hast"
+import { toString } from "hast-util-to-string"
+import { QuartzTransformerPlugin } from "../types"
+import { escapeHTML } from "../../util/escape"
+
+export interface Options {
+  descriptionLength: number
+  replaceExternalLinks: boolean
+}
+
+const defaultOptions: Options = {
+  descriptionLength: 150,
+  replaceExternalLinks: true,
+}
+
+const urlRegex = new RegExp(
+  /(https?:\/\/)?(?<domain>([\da-z\.-]+)\.([a-z\.]{2,6})(:\d+)?)(?<path>[\/\w\.-]*)(\?[\/\w\.=&;-]*)?/,
+  "g",
+)
+
+export const Description: QuartzTransformerPlugin<Partial<Options> | undefined> = (userOpts) => {
+  const opts = { ...defaultOptions, ...userOpts }
+  return {
+    name: "Description",
+    htmlPlugins() {
+      return [
+        () => {
+          return async (tree: HTMLRoot, file) => {
+            let frontMatterDescription = file.data.frontmatter?.description
+            let text = escapeHTML(toString(tree))
+
+            if (opts.replaceExternalLinks) {
+              frontMatterDescription = frontMatterDescription?.replace(
+                urlRegex,
+                "$<domain>" + "$<path>",
+              )
+              text = text.replace(urlRegex, "$<domain>" + "$<path>")
+            }
+
+            const desc = frontMatterDescription ?? text
+            const sentences = desc.replace(/\s+/g, " ").split(/\.\s/)
+            const finalDesc: string[] = []
+            const len = opts.descriptionLength
+            let sentenceIdx = 0
+            let currentDescriptionLength = 0
+
+            if (sentences[0] !== undefined && sentences[0].length >= len) {
+              const firstSentence = sentences[0].split(" ")
+              while (currentDescriptionLength < len) {
+                const sentence = firstSentence[sentenceIdx]
+                if (!sentence) break
+                finalDesc.push(sentence)
+                currentDescriptionLength += sentence.length
+                sentenceIdx++
+              }
+              finalDesc.push("...")
+            } else {
+              while (currentDescriptionLength < len) {
+                const sentence = sentences[sentenceIdx]
+                if (!sentence) break
+                const currentSentence = sentence.endsWith(".") ? sentence : sentence + "."
+                finalDesc.push(currentSentence)
+                currentDescriptionLength += currentSentence.length
+                sentenceIdx++
+              }
+            }
+
+            file.data.description = finalDesc.join(" ")
+            file.data.text = text
+          }
+        },
+      ]
+    },
+  }
+}
+
+declare module "vfile" {
+  interface DataMap {
+    description: string
+    text: string
+  }
+}