feat: allow custom before/after in pages

main.ts

@@ -122,14 +122,27 @@ export default class TagPagePlugin extends Plugin {
 			tagOfInterest,
 		);
 
+		if (!activeLeaf.file) {
+			return;
+		}
+
+		this.app.fileManager.processFrontMatter(activeLeaf.file, frontMatter => {
+			frontMatter[this.settings.frontmatterQueryProperty] = tagOfInterest
+			frontMatter.tags ??= [];
+			frontMatter.tags = [...new Set(frontMatter.tags).add('tag-page-md').add(tagOfInterest.slice(1) /* Omit the leading # */)]
+		})
+
+		const baseContent = await this.app.vault.read(activeLeaf.file);
 		const tagPageContentString = await generateTagPageContent(
 			this.app,
 			this.settings,
 			tagsInfo,
 			tagOfInterest,
+			baseContent,
 		);
 
 		swapPageContent(activeLeaf, tagPageContentString);
+		activeLeaf.save();
 	}
 
 	/**

src/utils/pageContent.ts

@@ -10,35 +10,64 @@ import { getIsWildCard } from './tagSearch';
  * @param {PluginSettings} settings - The plugin settings.
  * @param {TagInfo[]} tagsInfo - Information about tags.
  * @param {string} tagOfInterest - The tag for which the page is being generated.
+ * @param {string} baseContent - The original content of the page
  * @returns {Promise<string>} - The content to be set in the tag page.
  */
 export type GenerateTagPageContentFn = (
 	app: App,
 	settings: PluginSettings,
 	tagsInfo: TagInfo,
 	tagOfInterest: string,
+	baseContent?: string,
 ) => Promise<string>;
 
+const _parseContent = (
+	baseContent: string,
+) => {
+	const match = baseContent.match(
+		/^(?<frontmatter>---\n.*?\n---\n)?(?:(?<before>.*?)\n)?(?<tagpage>%%\ntag-page-md.*?tag-page-md end\n%%)(?:\n(?<after>.*?))?$/s,
+	);
+	if (!match || !match.groups) {
+		return { frontmatter: '', before: '', after: '' };
+	}
+	return {
+		frontmatter: match.groups.frontmatter ?? '',
+		before: match.groups.before ?? '',
+		after: match.groups.after ?? '',
+	};
+};
 /**
  * Generates the content for a tag page.
  *
  * @param {App} app - The Obsidian App instance.
  * @param {PluginSettings} settings - The plugin settings.
  * @param {TagInfo[]} tagsInfo - Information about tags.
  * @param {string} tagOfInterest - The tag for which the page is being generated.
+ * @param {string} baseContent - The original content of the page
  * @returns {Promise<string>} - The content to be set in the tag page.
  */
 export const generateTagPageContent: GenerateTagPageContentFn = async (
 	app: App,
 	settings: PluginSettings,
 	tagsInfo: TagInfo,
 	tagOfInterest: string,
+	baseContent = '',
 ): Promise<string> => {
 	// Generate list of links to files with this tag
 	const tagPageContent: string[] = [];
-	tagPageContent.push(
-		`---\n${settings.frontmatterQueryProperty}: "${tagOfInterest}"\n---`,
-	);
+
+	// Try to extract comments from the page to spot injection placeholder
+	const { frontmatter, before, after } = _parseContent(baseContent);
+
+	if(frontmatter){
+		tagPageContent.push(frontmatter);
+	}
+
+	if (before) {
+		tagPageContent.push(before);
+	}
+	tagPageContent.push('%%\ntag-page-md\n%%\n');
+
 	tagPageContent.push(`## Tag Content for ${tagOfInterest.replace('*', '')}`);
 
 	// Check if we have more than one baseTag across all tagInfos
@@ -85,6 +114,11 @@ export const generateTagPageContent: GenerateTagPageContentFn = async (
 		tagPageContent.push(`## Files with ${cleanedTag} in frontmatter`);
 		tagPageContent.push(...filesWithFrontmatterTag);
 	}
+
+	tagPageContent.push('\n%%\ntag-page-md end\n%%');
+	if (after) {
+		tagPageContent.push(after);
+	}
 	return tagPageContent.join('\n');
 };
 
@@ -103,8 +137,9 @@ export const extractFrontMatterTagValue = (
 ): string | undefined => {
 	if (view.file) {
 		try {
-			const metaMatter = app.metadataCache.getFileCache(view.file)
-				?.frontmatter;
+			const metaMatter = app.metadataCache.getFileCache(
+				view.file,
+			)?.frontmatter;
 
 			return metaMatter?.[frontMatterTag];
 		} catch (err) {