Add markdown-extension-collection.ts

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

src/components/markdown-renderer/hooks/use-convert-markdown-to-react-dom.ts

@@ -6,17 +6,15 @@
 
 import MarkdownIt from 'markdown-it/lib'
 import { useMemo } from 'react'
-import type { ComponentReplacer, ValidReactDomElement } from '../replace-components/component-replacer'
+import type { ValidReactDomElement } from '../replace-components/component-replacer'
 import convertHtmlToReact from '@hedgedoc/html-to-react'
 import { NodeToReactTransformer } from '../utils/node-to-react-transformer'
 import { LineIdMapper } from '../utils/line-id-mapper'
 import type { MarkdownExtension } from '../markdown-extension/markdown-extension'
-import type { NodeProcessor } from '../node-preprocessors/node-processor'
-import type { Document } from 'domhandler'
-import { SanitizerMarkdownExtension } from '../markdown-extension/sanitizer/sanitizer-markdown-extension'
+import { MarkdownExtensionCollection } from '../markdown-extension/markdown-extension-collection'
 
 /**
- * Renders markdown code into react elements
+ * Renders Markdown-Code into react elements
  *
  * @param markdownContentLines The markdown code lines that should be rendered
  * @param additionalMarkdownExtensions A list of {@link MarkdownExtension markdown extensions} that should be used
@@ -32,13 +30,10 @@ export const useConvertMarkdownToReactDom = (
 ): ValidReactDomElement[] => {
   const lineNumberMapper = useMemo(() => new LineIdMapper(), [])
   const htmlToReactTransformer = useMemo(() => new NodeToReactTransformer(), [])
-  const markdownExtensions = useMemo(() => {
-    const tagNameWhiteList = additionalMarkdownExtensions.reduce(
-      (state, extension) => [...state, ...extension.buildTagNameWhitelist()],
-      [] as string[]
-    )
-    return [...additionalMarkdownExtensions, new SanitizerMarkdownExtension(tagNameWhiteList)]
-  }, [additionalMarkdownExtensions])
+  const markdownExtensions = useMemo(
+    () => new MarkdownExtensionCollection(additionalMarkdownExtensions),
+    [additionalMarkdownExtensions]
+  )
 
   const markdownIt = useMemo(() => {
     const newMarkdownIt = new MarkdownIt('default', {
@@ -47,35 +42,19 @@ export const useConvertMarkdownToReactDom = (
       langPrefix: '',
       typographer: true
     })
-    markdownExtensions.forEach((extension) =>
-      newMarkdownIt.use((markdownIt) => extension.configureMarkdownIt(markdownIt))
-    )
-    markdownExtensions.forEach((extension) =>
-      newMarkdownIt.use((markdownIt) => extension.configureMarkdownItPost(markdownIt))
-    )
+    markdownExtensions.configureMarkdownIt(newMarkdownIt)
     return newMarkdownIt
   }, [allowHtml, markdownExtensions, newlinesAreBreaks])
 
   useMemo(() => {
-    const replacers = markdownExtensions.reduce(
-      (state, extension) => [...state, ...extension.buildReplacers()],
-      [] as ComponentReplacer[]
-    )
-    htmlToReactTransformer.setReplacers(replacers)
+    htmlToReactTransformer.setReplacers(markdownExtensions.buildReplacers())
   }, [htmlToReactTransformer, markdownExtensions])
 
   useMemo(() => {
     htmlToReactTransformer.setLineIds(lineNumberMapper.updateLineMapping(markdownContentLines))
   }, [htmlToReactTransformer, lineNumberMapper, markdownContentLines])
 
-  const nodePreProcessor = useMemo(() => {
-    return markdownExtensions
-      .reduce((state, extension) => [...state, ...extension.buildNodeProcessors()], [] as NodeProcessor[])
-      .reduce(
-        (state, processor) => (document: Document) => state(processor.process(document)),
-        (document: Document) => document
-      )
-  }, [markdownExtensions])
+  const nodePreProcessor = useMemo(() => markdownExtensions.buildFlatNodeProcessor(), [markdownExtensions])
 
   return useMemo(() => {
     const html = markdownIt.render(markdownContentLines.join('\n'))

src/components/markdown-renderer/markdown-extension/markdown-extension-collection.ts

@@ -0,0 +1,57 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import type { MarkdownExtension } from './markdown-extension'
+import type { ComponentReplacer } from '../replace-components/component-replacer'
+import type { Document } from 'domhandler'
+import type MarkdownIt from 'markdown-it'
+import { SanitizerMarkdownExtension } from './sanitizer/sanitizer-markdown-extension'
+
+/**
+ * Contains multiple {@link MarkdownExtension} and uses them to configure parts of the renderer.
+ */
+export class MarkdownExtensionCollection {
+  private extensions: MarkdownExtension[]
+
+  public constructor(additionalExtensions: MarkdownExtension[]) {
+    const tagWhiteLists = additionalExtensions.flatMap((extension) => extension.buildTagNameWhitelist())
+
+    this.extensions = [...additionalExtensions, new SanitizerMarkdownExtension(tagWhiteLists)]
+  }
+
+  /**
+   * Configures the given {@link MarkdownIt markdown-it instance} using every saved {@link MarkdownExtension extension}.
+   *
+   * @param markdownIt The markdown-it instance to configure.
+   */
+  public configureMarkdownIt(markdownIt: MarkdownIt): void {
+    this.extensions.forEach((extension) => markdownIt.use((markdownIt) => extension.configureMarkdownIt(markdownIt)))
+    this.extensions.forEach((extension) =>
+      markdownIt.use((markdownIt) => extension.configureMarkdownItPost(markdownIt))
+    )
+  }
+
+  /**
+   * Creates a node processor that applies the node processor of every saved {@link MarkdownExtension extension}.
+   *
+   * @return the created node processor function
+   */
+  public buildFlatNodeProcessor(): (document: Document) => Document {
+    return this.extensions
+      .flatMap((extension) => extension.buildNodeProcessors())
+      .reduce(
+        (state, processor) => (document: Document) => state(processor.process(document)),
+        (document: Document) => document
+      )
+  }
+
+  /**
+   * Collects all {@link ComponentReplacer component replacers} from all saved {@link MarkdownExtension extension}.
+   */
+  public buildReplacers(): ComponentReplacer[] {
+    return this.extensions.flatMap((extension) => extension.buildReplacers())
+  }
+}