feat: add support for wiki-style link and image Markdown syntax

src/markdownit/index.js

@@ -19,6 +19,7 @@ import preview from './preview.js'
 import splitMixedLists from './splitMixedLists.js'
 import taskLists from './taskLists.ts'
 import underline from './underline.js'
+import wikiLinks from './wikiLinks.ts'
 
 const markdownit = MarkdownIt('commonmark', { html: false, breaks: false })
 	.enable('strikethrough')
@@ -33,6 +34,7 @@ const markdownit = MarkdownIt('commonmark', { html: false, breaks: false })
 	.use(preview)
 	.use(keepSyntax)
 	.use(markdownitMentions)
+	.use(wikiLinks)
 	.use(implicitFigures)
 	.use(mark)
 	.use(mathematics)

src/markdownit/wikiLinks.ts

@@ -0,0 +1,116 @@
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+import type MarkdownIt from 'markdown-it'
+
+/**
+ * markdown-it plugin: parse Obsidian-style wiki links and wiki image links
+ *
+ * Produces
+ * Produces a standard `link` or `image` token so that downstream plugins
+ * treat it exactly like a normal link/image.
+ *
+ * A `data-wiki-image` or `data-wiki-link` attribute is set so the ProseMirror
+ * serializer can round-trip the syntax back to the wiki style link/image syntax.
+ *
+ * @param md - The markdown-it instance to extend
+ */
+export default function wikiLinks(md: MarkdownIt): void {
+	// Parse wiki image links `![[filename]]`
+	md.inline.ruler.before('image', 'wiki_image_link', (state, silent) => {
+		const src = state.src
+		const pos = state.pos
+
+		// Must start with ![[
+		if (src.charCodeAt(pos) !== 0x21 /* ! */) return false
+		if (src.charCodeAt(pos + 1) !== 0x5b /* [ */) return false
+		if (src.charCodeAt(pos + 2) !== 0x5b /* [ */) return false
+
+		// Find the closing ]] — no newlines allowed inside
+		let end = pos + 3
+		while (end < src.length) {
+			const ch = src.charCodeAt(end)
+			if (ch === 0x0a /* \n */) return false
+			if (ch === 0x5d /* ] */ && src.charCodeAt(end + 1) === 0x5d /* ] */)
+				break
+			end++
+		}
+		if (end >= src.length) return false
+
+		const filename = src.slice(pos + 3, end)
+		if (!filename) return false
+
+		if (silent) return true
+
+		const token = state.push('image', 'img', 0)
+		token.attrs = [
+			['src', filename],
+			['alt', ''],
+			['data-wiki-image', 'true'],
+		]
+		// Alt text is derived from token.children by the renderer
+		const altToken = new state.Token('text', '', 0)
+		altToken.content = filename
+		token.children = [altToken]
+		token.content = filename
+
+		state.pos = end + 2
+		return true
+	})
+
+	// Parse wiki links `[[link]]`
+	md.inline.ruler.before('link', 'wiki_link', (state, silent) => {
+		const src = state.src
+		const pos = state.pos
+
+		// Must start with [[
+		if (src.charCodeAt(pos) !== 0x5b /* [ */) return false
+		if (src.charCodeAt(pos + 1) !== 0x5b /* [ */) return false
+
+		// Prevent matching `[[` that is itself preceded by `[` (e.g. `[[[foo]]]`)
+		if (pos > 0 && src.charCodeAt(pos - 1) === 0x5b /* [ */) return false
+
+		// Find the closing ]] — no newlines allowed inside
+		let end = pos + 2
+		while (end < src.length) {
+			const ch = src.charCodeAt(end)
+			if (ch === 0x0a /* \n */) return false
+			if (ch === 0x5d /* ] */ && src.charCodeAt(end + 1) === 0x5d /* ] */)
+				break
+			end++
+		}
+		if (end >= src.length) return false
+
+		const content = src.slice(pos + 2, end)
+		if (!content) return false
+
+		// Split on first | to get target and optional display text
+		const pipeIdx = content.indexOf('|')
+		const target = pipeIdx === -1 ? content : content.slice(0, pipeIdx)
+		const displayText = pipeIdx === -1 ? content : content.slice(pipeIdx + 1)
+
+		if (!target) return false
+
+		// Reject targets containing characters that conflict with CommonMark inline syntax
+		// ([, ], * are not valid in file names on most systems anyway)
+		if (/[[\]*]/.test(target)) return false
+
+		if (silent) return true
+
+		const tokenOpen = state.push('link_open', 'a', 1)
+		tokenOpen.attrs = [
+			['href', target],
+			['data-wiki-link', 'true'],
+		]
+
+		const tokenText = state.push('text', '', 0)
+		tokenText.content = displayText
+
+		state.push('link_close', 'a', -1)
+
+		state.pos = end + 2
+		return true
+	})
+}

src/marks/Link.ts

@@ -7,6 +7,9 @@ import type { ExtendedRegExpMatchArray } from '@tiptap/core'
 import { getMarkRange, isMarkActive, markInputRule } from '@tiptap/core'
 import type { LinkOptions } from '@tiptap/extension-link'
 import TipTapLink, { isAllowedUri } from '@tiptap/extension-link'
+import type { Mark, Node } from '@tiptap/pm/model'
+import type { MarkdownSerializerState } from 'prosemirror-markdown'
+import { defaultMarkdownSerializer } from 'prosemirror-markdown'
 import { domHref, parseHref } from '../helpers/links.js'
 import { linkClicking } from '../plugins/links.js'
 
@@ -107,6 +110,13 @@ const Link = TipTapLink.extend<RelativePathLinkOptions>({
 			title: {
 				default: null,
 			},
+			isWikiLink: {
+				default: false,
+				parseHTML: (element) =>
+					element.getAttribute('data-wiki-link') === 'true',
+				renderHTML: (attrs) =>
+					attrs.isWikiLink ? { 'data-wiki-link': 'true' } : {},
+			},
 		}
 	},
 
@@ -239,6 +249,51 @@ const Link = TipTapLink.extend<RelativePathLinkOptions>({
 		// Add our own click handler plugin
 		return [...plugins, linkClicking()]
 	},
+
+	// @ts-expect-error - toMarkdown is a custom field not part of the official Tiptap API
+	toMarkdown: {
+		open(
+			state: MarkdownSerializerState,
+			mark: Mark,
+			parent: Node,
+			index: number,
+		) {
+			if (!mark.attrs.isWikiLink) {
+				const open = defaultMarkdownSerializer.marks.link.open
+				return typeof open === 'function'
+					? open(state, mark, parent, index)
+					: open
+			}
+			const href = mark.attrs.href as string
+			// Collect the display text of this mark's span to decide the form
+			let innerText = ''
+			parent.descendants((child) => {
+				if (!mark.isInSet(child.marks)) {
+					return false
+				}
+				if (child.isText) {
+					innerText += child.text
+				}
+			})
+			return innerText === href ? `[[` : `[[${href}|`
+		},
+		close(
+			state: MarkdownSerializerState,
+			mark: Mark,
+			_parent: Node,
+			_index: number,
+		) {
+			if (!mark.attrs.isWikiLink) {
+				const close = defaultMarkdownSerializer.marks.link.close
+				return typeof close === 'function'
+					? close(state, mark, _parent, _index)
+					: close
+			}
+			return ']]'
+		},
+		mixable: true,
+		expelEnclosingWhitespace: false,
+	},
 })
 
 export default Link

src/nodes/Image.js

@@ -17,6 +17,19 @@ const imageExtractAttachmentsKey = new PluginKey('imageExtractAttachments')
 const Image = TiptapImage.extend({
 	selectable: false,
 
+	addAttributes() {
+		return {
+			...this.parent?.(),
+			isWikiLink: {
+				default: false,
+				parseHTML: (element) =>
+					element.getAttribute('data-wiki-image') === 'true',
+				renderHTML: (attrs) =>
+					attrs.isWikiLink ? { 'data-wiki-image': 'true' } : {},
+			},
+		}
+	},
+
 	parseHTML() {
 		return [
 			{
@@ -118,8 +131,12 @@ const Image = TiptapImage.extend({
 
 	/* Serializes an image node as a block image, so it ensures an image is always a block by itself */
 	toMarkdown(state, node, parent, index) {
-		node.attrs.alt = node.attrs.alt.toString()
-		defaultMarkdownSerializer.nodes.image(state, node, parent, index)
+		if (node.attrs.isWikiLink) {
+			state.write(`![[${node.attrs.src}]]`)
+		} else {
+			node.attrs.alt = node.attrs.alt.toString()
+			defaultMarkdownSerializer.nodes.image(state, node, parent, index)
+		}
 		state.closeBlock(node)
 	},
 })

src/nodes/ImageInline.js

@@ -18,6 +18,19 @@ const ImageInline = TiptapImage.extend({
 
 	selectable: false,
 
+	addAttributes() {
+		return {
+			...this.parent?.(),
+			isWikiLink: {
+				default: false,
+				parseHTML: (element) =>
+					element.getAttribute('data-wiki-image') === 'true',
+				renderHTML: (attrs) =>
+					attrs.isWikiLink ? { 'data-wiki-image': 'true' } : {},
+			},
+		}
+	},
+
 	parseHTML() {
 		return [
 			{
@@ -50,7 +63,11 @@ const ImageInline = TiptapImage.extend({
 	},
 
 	toMarkdown(state, node, parent, index) {
-		return defaultMarkdownSerializer.nodes.image(state, node, parent, index)
+		if (node.attrs.isWikiLink) {
+			state.write(`![[${node.attrs.src}]]`)
+		} else {
+			return defaultMarkdownSerializer.nodes.image(state, node, parent, index)
+		}
 	},
 })
 

src/tests/extensions/Markdown.spec.js

@@ -211,6 +211,26 @@ describe('Markdown extension integrated in the editor', () => {
 		expect(text).toBe('Hello\n\nexample@example.com')
 		editor.destroy()
 	})
+
+	it('serializes a wiki text link as [[target]]', () => {
+		const editor = createCustomEditor(
+			'<p><a href="WikiLink" data-wiki-link="true">WikiLink</a></p>',
+			[Markdown, Link],
+		)
+		const serializer = createMarkdownSerializer(editor.schema)
+		expect(serializer.serialize(editor.state.doc)).toBe('[[WikiLink]]')
+		editor.destroy()
+	})
+
+	it('serializes a wiki text link with display text as [[target|display]]', () => {
+		const editor = createCustomEditor(
+			'<p><a href="target" data-wiki-link="true">display</a></p>',
+			[Markdown, Link],
+		)
+		const serializer = createMarkdownSerializer(editor.schema)
+		expect(serializer.serialize(editor.state.doc)).toBe('[[target|display]]')
+		editor.destroy()
+	})
 })
 
 const copyEditorContent = (editor, nodeType = null) => {