fix(preview): allow preview for links followed by whitespace

Signed-off-by: Max <max@nextcloud.com>

cypress/e2e/nodes/Preview.spec.js

@@ -28,7 +28,7 @@ import { createCustomEditor } from './../../support/components.js'
 import testData from '../../fixtures/Preview.md'
 import { loadMarkdown, runCommands, expectMarkdown } from './helpers.js'
 
-describe.only('Preview extension', { retries: 0 }, () => {
+describe('Preview extension', { retries: 0 }, () => {
 
 	const editor = createCustomEditor({
 		content: '',
@@ -71,23 +71,34 @@ describe.only('Preview extension', { retries: 0 }, () => {
 			expect(editor.can().setPreview()).to.be.false
 		})
 
-		it('can run on a paragraph with a link', () => {
+		it('convert a paragraph with a link', () => {
 			prepareEditor('[link text](https://nextcloud.com)\n')
-			expect(editor.can().setPreview()).to.be.true
+			editor.commands.setPreview()
+			expectPreview()
 		})
 
-		it('can run the second a paragraph with a link', () => {
+		it('convert the second a paragraph with a link', () => {
 			prepareEditor('hello\n\n[link text](https://nextcloud.com)\n')
 			editor.commands.setTextSelection(10)
-			expect(editor.can().setPreview()).to.be.true
+			editor.commands.setPreview()
+			expectPreview()
+		})
+
+		it('convert a paragraph with a link and a space', () => {
+			prepareEditor('[link text](https://nextcloud.com)\n')
+			editor.commands.insertContentAt(
+				editor.state.doc.content.size - 1,
+				' ',
+				{ updateSelection: false },
+			)
+			editor.commands.setPreview()
+			expectPreview()
 		})
 
 		it('results in a preview node with the href and text with link mark', () => {
 			prepareEditor('[link text](https://nextcloud.com)\n')
 			editor.commands.setPreview()
-			expect(getParentNode().type.name).to.equal('preview')
-			expect(getParentNode().attrs.href).to.equal('https://nextcloud.com')
-			expect(getMark().attrs.href).to.equal('https://nextcloud.com')
+			expectPreview()
 		})
 
 		it('cannot run twice', () => {
@@ -131,6 +142,15 @@ describe.only('Preview extension', { retries: 0 }, () => {
 
 	})
 
+	/**
+	 *  Expect a preview in the editor.
+	 */
+	function expectPreview() {
+		expect(getParentNode().type.name).to.equal('preview')
+		expect(getParentNode().attrs.href).to.equal('https://nextcloud.com')
+		expect(getMark().attrs.href).to.equal('https://nextcloud.com')
+	}
+
 	/**
 	 *
 	 */

cypress/fixtures/Preview.md

@@ -14,10 +14,10 @@ empty
 
 [link text](https://nextcloud.com)
 
-## Preserves a link preview
+## Preserves a link preview - TODO
 
 [link text](https://nextcloud.com (Preview))
 
 ---
 
-[link text](https://nextcloud.com (Preview))
+[link text](https://nextcloud.com "Preview")

src/nodes/Preview.js

@@ -137,7 +137,7 @@ function isPreview(typeOrName, attributes, state) {
  */
 function previewPossible({ selection }) {
 	const { $from } = selection
-	if (childCount($from.parent) > 1) {
+	if (hasOtherContent($from.parent)) {
 		return false
 	}
 	const href = extractHref($from.nodeAfter)
@@ -147,6 +147,15 @@ function previewPossible({ selection }) {
 	return true
 }
 
+/**
+ * Does the node contain more content than the first child
+ * @param node - node to inspect
+ */
+function hasOtherContent(node) {
+	return childCount(node) > 2
+		|| ( childCount(node) === 2 && node.lastChild.textContent.trim() )
+}
+
 /**
  *
  * @param node