Add dev server with livereload

npm run dev starts a dev server on port 8080 serving the test
page and ribbit dist files. Watches src/ and test/integration/
for changes, rebuilds automatically, and notifies connected
browsers to reload via EventSource on port 8081.

The test page includes a livereload script that auto-reloads
when the dev server signals a rebuild.

package.json

@@ -14,6 +14,7 @@
     "build:core": "esbuild src/ts/ribbit-core.ts --bundle --format=iife --global-name=ribbit --sourcemap --outfile=dist/ribbit/ribbit-core.js",
     "build:core-min": "esbuild src/ts/ribbit-core.ts --bundle --format=iife --global-name=ribbit --minify --outfile=dist/ribbit/ribbit-core.min.js",
     "build:css": "cp src/static/ribbit-core.css dist/ribbit/ && cp -r src/static/themes dist/ribbit/",
+    "dev": "npm run build && node test/integration/dev-server.js",
     "test": "npm run build && jest --verbose",
     "test:integration": "npm run build && node test/integration/test.js && node test/integration/test_wysiwyg.js",
     "test:coverage": "npm run build && jest --coverage"

src/ts/ribbit-editor.ts

@@ -90,9 +90,7 @@ export class RibbitEditor extends Ribbit {
             if (this.state !== this.states.WYSIWYG) {
                 return;
             }
-            if (event.key === 'Enter') {
-                this.handleEnter(event);
-            }
+            this.dispatchKeydown(event);
         });
 
         this.element.addEventListener('keyup', (event: KeyboardEvent) => {
@@ -212,7 +210,9 @@ export class RibbitEditor extends Ribbit {
         while (node && node !== this.element) {
             if (node.nodeType === 1) {
                 const element = node as HTMLElement;
-                if (element.tagName === 'LI' || element.parentNode === this.element) {
+                if (element.tagName === 'LI'
+                    || (element.tagName === 'P' && element.parentElement?.tagName === 'BLOCKQUOTE')
+                    || element.parentNode === this.element) {
                     return element;
                 }
             }
@@ -235,6 +235,17 @@ export class RibbitEditor extends Ribbit {
         // Normalize   → space so patterns like "- " and "> " match
         const text = (block.textContent || '').replace(/\u00A0/g, ' ');
 
+        // If the block contains <br> elements, check the current line
+        // (text after the last <br> before the cursor). Block-level
+        // patterns at the start of a line after <br> should split the
+        // block and transform the new portion.
+        const currentLineText = this.getCurrentLineText(block);
+        if (currentLineText !== null && currentLineText !== text) {
+            if (this.tryBlockTransformOnCurrentLine(block, currentLineText)) {
+                return;
+            }
+        }
+
         const headingMatch = text.match(/^(#{1,6})\s/);
         if (headingMatch) {
             const level = headingMatch[1].length;
@@ -315,6 +326,12 @@ export class RibbitEditor extends Ribbit {
             return '';
         }
         const element = node as HTMLElement;
+
+        // Preserve <br> as a newline so blockquote line breaks survive
+        if (element.tagName === 'BR') {
+            return '\n';
+        }
+
         const specDelim = element.getAttribute('data-speculative');
 
         if (specDelim) {
@@ -358,6 +375,167 @@ export class RibbitEditor extends Ribbit {
      * Sentinel markers (\x01...\x02) prevent the regex from matching
      * delimiters that belong to already-transformed elements.
      */
+    /**
+     * Get the text of the current line within a block — the text
+     * after the last <br> before the cursor. Returns null if there
+     * are no <br> elements (single-line block).
+     */
+    private getCurrentLineText(block: HTMLElement): string | null {
+        const hasBr = block.querySelector('br');
+        if (!hasBr) {
+            return null;
+        }
+        const selection = window.getSelection();
+        if (!selection || selection.rangeCount === 0) {
+            return null;
+        }
+        // Collect text from the cursor's text node backward to the
+        // nearest <br> or start of block
+        let node: Node | null = selection.anchorNode;
+        if (!node || !block.contains(node)) {
+            return null;
+        }
+        // Get text from cursor position to start of current text node
+        let lineText = '';
+        if (node.nodeType === 3) {
+            lineText = (node.textContent || '').slice(0, selection.anchorOffset);
+        }
+        // Walk backward through siblings collecting text until we hit a <br>
+        let sibling: Node | null = node.nodeType === 3
+            ? node.previousSibling
+            : null;
+        while (sibling) {
+            if (sibling.nodeType === 1 && (sibling as HTMLElement).tagName === 'BR') {
+                break;
+            }
+            lineText = (sibling.textContent || '') + lineText;
+            sibling = sibling.previousSibling;
+        }
+        // Only return if we actually found a <br> (meaning this is a
+        // subsequent line, not the first line of the block)
+        if (!sibling) {
+            return null;
+        }
+        return lineText.replace(/\u00A0/g, ' ').replace(/\u200B/g, '');
+    }
+
+    /**
+     * Check if a block-level pattern matches on the current line text.
+     * If so, split the block at the <br> before this line and transform
+     * the new block.
+     */
+    private tryBlockTransformOnCurrentLine(block: HTMLElement, lineText: string): boolean {
+        let newTag: string | null = null;
+        let prefixLength = 0;
+
+        const headingMatch = lineText.match(/^(#{1,6})\s/);
+        if (headingMatch) {
+            newTag = 'H' + headingMatch[1].length;
+            prefixLength = headingMatch[0].length;
+        } else if (lineText.startsWith('> ')) {
+            newTag = 'BLOCKQUOTE';
+            prefixLength = 2;
+        } else if (/^[-*+]\s/.test(lineText)) {
+            return this.splitAndTransformList(block, 'ul', lineText);
+        } else if (/^\d+\.\s/.test(lineText)) {
+            return this.splitAndTransformList(block, 'ol', lineText);
+        } else if (/^(\*{3,}|-{3,}|_{3,})\s*$/.test(lineText)) {
+            this.splitAtCurrentLine(block);
+            // The split created a new <p> with the hr text — transform it
+            const newBlock = block.nextElementSibling as HTMLElement;
+            if (newBlock) {
+                const hr = document.createElement('hr');
+                const paragraph = document.createElement('p');
+                paragraph.innerHTML = '<br>';
+                newBlock.replaceWith(hr, paragraph);
+                const range = document.createRange();
+                range.setStart(paragraph, 0);
+                range.collapse(true);
+                const selection = window.getSelection()!;
+                selection.removeAllRanges();
+                selection.addRange(range);
+            }
+            return true;
+        }
+
+        if (!newTag) {
+            return false;
+        }
+
+        this.splitAtCurrentLine(block);
+        const newBlock = block.nextElementSibling as HTMLElement;
+        if (newBlock) {
+            this.replaceBlock(newBlock, newTag, prefixLength);
+        }
+        return true;
+    }
+
+    /**
+     * Split a block at the <br> before the current line. Everything
+     * after the <br> becomes a new <p> element after the original block.
+     */
+    private splitAtCurrentLine(block: HTMLElement): void {
+        const selection = window.getSelection();
+        if (!selection || selection.rangeCount === 0) {
+            return;
+        }
+        let node: Node | null = selection.anchorNode;
+
+        // Find the <br> before the current line
+        let brNode: Node | null = null;
+        if (node?.nodeType === 3) {
+            let sibling: Node | null = node.previousSibling;
+            while (sibling) {
+                if (sibling.nodeType === 1 && (sibling as HTMLElement).tagName === 'BR') {
+                    brNode = sibling;
+                    break;
+                }
+                sibling = sibling.previousSibling;
+            }
+        }
+
+        if (!brNode) {
+            return;
+        }
+
+        // Collect all nodes after the <br> into a new <p>
+        const newParagraph = document.createElement('p');
+        let nextNode: Node | null = brNode.nextSibling;
+        while (nextNode) {
+            const following = nextNode.nextSibling;
+            newParagraph.appendChild(nextNode);
+            nextNode = following;
+        }
+        // Strip leading ZWS from the first text node — it was a cursor
+        // anchor from the Enter handler, not real content
+        const firstChild = newParagraph.firstChild;
+        if (firstChild && firstChild.nodeType === 3) {
+            firstChild.textContent = (firstChild.textContent || '').replace(/^\u200B+/, '');
+        }
+        brNode.parentNode?.removeChild(brNode);
+
+        // Remove trailing empty text nodes and <br> from the original block
+        while (block.lastChild
+            && ((block.lastChild.nodeType === 3
+                && (block.lastChild.textContent || '').replace(/\u200B/g, '').trim() === '')
+                || (block.lastChild.nodeType === 1
+                    && (block.lastChild as HTMLElement).tagName === 'BR'))) {
+            block.removeChild(block.lastChild);
+        }
+
+        block.after(newParagraph);
+    }
+
+    private splitAndTransformList(block: HTMLElement, listTag: string, lineText: string): boolean {
+        const prefixLength = lineText.indexOf(' ') + 1;
+        this.splitAtCurrentLine(block);
+        const newBlock = block.nextElementSibling as HTMLElement;
+        if (newBlock) {
+            this.replaceBlockWithList(newBlock, listTag, prefixLength);
+        }
+        return true;
+    }
+
     private transformInline(block: HTMLElement): void {
         const selection = window.getSelection();
         if (!selection || selection.rangeCount === 0) {
@@ -369,6 +547,11 @@ export class RibbitEditor extends Ribbit {
             return;
         }
 
+        // Normalize flanking underscores to asterisks so _ triggers
+        // the same live preview as *. The CSS pseudo-elements will
+        // show * even though the user typed _.
+        markdown = this.normalizeUnderscores(markdown);
+
         // Nesting rules: which elements must not appear inside which
         const forbiddenChildren = RibbitEditor.forbiddenNesting;
 
@@ -413,6 +596,38 @@ export class RibbitEditor extends Ribbit {
      * If an unclosed opener was found, wrap the trailing content in
      * a speculative element; otherwise set innerHTML directly.
      */
+    /**
+     * Convert flanking underscore runs to asterisks so the delimiter
+     * matching treats _ the same as *. Non-flanking underscores (like
+     * foo_bar) are left alone. Backslash-escaped underscores (\_) are
+     * protected from normalization.
+     */
+    private normalizeUnderscores(text: string): string {
+        const escapePlaceholder = '\x00U\x00';
+        const safeText = text.replace(/\\_/g, escapePlaceholder);
+
+        const punctuation = `[\\s.,;:!?'"()\\[\\]{}<>\\-/\\\\~#@&^|*\`]`;
+        const openRun = new RegExp(
+            `(?<=^|${punctuation})` +
+            `(_+)` +
+            `(?=\\S)`,
+            'g'
+        );
+        const closeRun = new RegExp(
+            `(?<=\\S)` +
+            `(_+)` +
+            `(?=$|${punctuation})`,
+            'g'
+        );
+        const toAsterisks = (_match: string, run: string) =>
+            '*'.repeat(run.length);
+        const normalized = safeText
+            .replace(openRun, toAsterisks)
+            .replace(closeRun, toAsterisks);
+
+        return normalized.replace(/\x00U\x00/g, '\\_');
+    }
+
     private rebuildBlock(
         block: HTMLElement,
         markdown: string,
@@ -420,7 +635,7 @@ export class RibbitEditor extends Ribbit {
         forbiddenChildren: Record<string, string[]>,
     ): void {
         if (!opener) {
-            block.innerHTML = markdown;
+            block.innerHTML = markdown.replace(/\n/g, '<br>\u200B');
             this.sanitizeNesting(block);
             this.appendZwsIfNeeded(block);
             this.placeCursorAtEnd(block);
@@ -434,7 +649,7 @@ export class RibbitEditor extends Ribbit {
         const probe = document.createElement('div');
         probe.innerHTML = inside;
         if (banned && banned.some(tag => probe.querySelector(tag))) {
-            block.innerHTML = markdown;
+            block.innerHTML = markdown.replace(/\n/g, '<br>\u200B');
             this.sanitizeNesting(block);
             this.appendZwsIfNeeded(block);
             this.placeCursorAtEnd(block);
@@ -501,6 +716,30 @@ export class RibbitEditor extends Ribbit {
     private replaceBlock(block: HTMLElement, newTag: string, prefixLength: number): void {
         const newEl = document.createElement(newTag);
         const content = (block.textContent || '').slice(prefixLength);
+        // Blockquotes need inner <p> elements so Enter can create
+        // sibling paragraphs within the quote
+        if (newTag === 'BLOCKQUOTE') {
+            const paragraph = document.createElement('p');
+            if (content) {
+                paragraph.textContent = content;
+            } else {
+                paragraph.innerHTML = '<br>';
+            }
+            newEl.appendChild(paragraph);
+            block.replaceWith(newEl);
+            newEl.classList.add('ribbit-editing');
+            const range = document.createRange();
+            if (paragraph.firstChild && paragraph.firstChild.nodeType === 3) {
+                range.setStart(paragraph.firstChild, 0);
+            } else {
+                range.setStart(paragraph, 0);
+            }
+            range.collapse(true);
+            const selection = window.getSelection()!;
+            selection.removeAllRanges();
+            selection.addRange(range);
+            return;
+        }
         if (content) {
             newEl.textContent = content;
         } else {
@@ -554,11 +793,56 @@ export class RibbitEditor extends Ribbit {
      * On Enter, strip editing decorations from the current block so
      * the browser's default newline behavior creates a clean element.
      */
-    private handleEnter(_event: KeyboardEvent): void {
-        const prev = this.element.querySelector('.ribbit-editing');
-        if (prev) {
-            prev.classList.remove('ribbit-editing');
-            prev.removeAttribute('data-speculative');
+    /**
+     * Dispatch a keydown event to the tag that contains the cursor.
+     * Walks up from the cursor to find a tag with handleKeydown,
+     * which routes to named handlers in the tag's eventHandlers map.
+     * If no tag handles the event, the browser's default runs.
+     */
+    private dispatchKeydown(event: KeyboardEvent): void {
+        // Strip editing decorations on Enter regardless of tag handling
+        if (event.key === 'Enter') {
+            const prev = this.element.querySelector('.ribbit-editing');
+            if (prev) {
+                prev.classList.remove('ribbit-editing');
+                prev.removeAttribute('data-speculative');
+            }
+        }
+
+        const selection = window.getSelection();
+        if (!selection || selection.rangeCount === 0) {
+            return;
+        }
+
+        // Walk up from the cursor to find a tag with handleKeydown.
+        // Skip <p> elements inside container blocks (blockquote, li)
+        // so the container's handler runs instead.
+        const containerTags = new Set(['BLOCKQUOTE', 'LI']);
+        let node: Node | null = selection.anchorNode;
+        while (node && node !== this.element) {
+            if (node.nodeType === 1) {
+                const element = node as HTMLElement;
+                // Skip <p> inside containers — let the container handle it
+                if (element.tagName === 'P' && element.parentElement
+                    && containerTags.has(element.parentElement.tagName)) {
+                    node = node.parentNode;
+                    continue;
+                }
+                const tag = this.converter.getBlockTags().find(
+                    blockTag => typeof blockTag.selector === 'string'
+                        && blockTag.selector.split(',').some(
+                            selector => element.tagName === selector.trim()
+                        )
+                );
+                if (tag?.handleKeydown) {
+                    const handled = tag.handleKeydown(element, event, selection, this);
+                    if (handled) {
+                        event.preventDefault();
+                        return;
+                    }
+                }
+            }
+            node = node.parentNode;
         }
     }
 
@@ -705,7 +989,11 @@ export class RibbitEditor extends Ribbit {
             return decodeHtmlEntities(html);
         }
         if (this.getState() === this.states.WYSIWYG || this.getState() === this.states.VIEW) {
-            return this.htmlToMarkdown(this.element.innerHTML);
+            // Normalize non-breaking spaces and strip zero-width spaces
+            // that the WYSIWYG transform inserts for cursor positioning
+            return this.htmlToMarkdown(this.element.innerHTML)
+                .replace(/\u00A0/g, ' ')
+                .replace(/\u200B/g, '');
         }
         // Before run() — element has raw markdown as text
         return this.element.textContent || '';
@@ -720,6 +1008,8 @@ export class RibbitEditor extends Ribbit {
     wysiwyg(): void {
         if (this.getState() === this.states.WYSIWYG) return;
         const wasEditing = this.getState() === this.states.EDIT;
+        // Invalidate cache so getHTML() re-converts from current content
+        this.invalidateCache();
         this.vim?.detach();
         this.collaboration?.connect();
         if (wasEditing && this.collaboration?.isPaused()) {

src/ts/ribbit.ts

@@ -271,6 +271,7 @@ export class Ribbit {
      */
     view(): void {
         if (this.getState() === this.states.VIEW) return;
+        this.invalidateCache();
         this.collaboration?.disconnect();
         this.element.innerHTML = this.getHTML();
         this.setState(this.states.VIEW);

src/ts/tags.ts

@@ -132,13 +132,219 @@ export function inlineTag(def: InlineTagDef): Tag {
     };
 }
 
+/**
+ * Base class for block-level tags. Provides keyboard event dispatch
+ * for WYSIWYG mode: subclasses populate `eventHandlers` with named
+ * handlers (e.g. 'onEnter', 'onBackspace'), and `handleKeydown`
+ * routes events to the matching handler.
+ *
+ *   class MyTag extends BaseTag implements Tag {
+ *       eventHandlers = { 'onEnter': this.onEnter };
+ *       private onEnter(element: HTMLElement, selection: Selection): boolean { ... }
+ *   }
+ */
+class BaseTag {
+    eventHandlers: Record<string, (element: HTMLElement, selection: Selection, editor: any) => boolean> = {};
+
+    handleKeydown(element: HTMLElement, event: KeyboardEvent, selection: Selection, editor: any): boolean {
+        const handlerName = 'on' + event.key;
+        const handler = this.eventHandlers[handlerName];
+        if (handler) {
+            return handler.call(this, element, selection, editor);
+        }
+        // Default Enter behavior: insert <br> for single Enter,
+        // exit block for double Enter (empty line after <br>)
+        if (event.key === 'Enter') {
+            return this.defaultOnEnter(element, selection, editor);
+        }
+        if (event.key === 'Backspace') {
+            return this.defaultOnBackspace(element, selection);
+        }
+        return false;
+    }
+
+    /**
+     * Default Enter handler for all block tags. Inserts a <br> for
+     * line continuation. If the cursor is on an empty line (right
+     * after a <br> with no content following), removes the trailing
+     * <br> and creates a new <p> after the current block.
+     */
+    /**
+     * Default Backspace handler. When the cursor is at the start of
+     * a line after a <br> (i.e. on the ZWS cursor anchor), remove
+     * the <br> and ZWS to join the lines. Otherwise let the browser
+     * handle it.
+     */
+    private defaultOnBackspace(element: HTMLElement, selection: Selection): boolean {
+        const range = selection.getRangeAt(0);
+        const container = range.startContainer;
+        const offset = range.startOffset;
+
+        if (container.nodeType !== 3) {
+            return false;
+        }
+
+        const zeroWidthSpace = /\u200B/g;
+        const textBefore = (container.textContent || '').slice(0, offset).replace(zeroWidthSpace, '');
+
+        // Only intercept if cursor is at the start of the line
+        // (nothing but ZWS before the cursor in this text node)
+        if (textBefore !== '') {
+            return false;
+        }
+
+        // Walk back past empty text nodes to find a <br>
+        let previous: Node | null = container.previousSibling;
+        while (previous && previous.nodeType === 3
+            && (previous.textContent || '').replace(zeroWidthSpace, '').trim() === '') {
+            previous = previous.previousSibling;
+        }
+
+        if (!previous || previous.nodeType !== 1 || (previous as HTMLElement).tagName !== 'BR') {
+            return false;
+        }
+
+        // Remove the <br> and any ZWS/empty text nodes between it
+        // and the cursor's text node
+        let nodeToRemove: Node | null = container.previousSibling;
+        while (nodeToRemove && nodeToRemove !== previous) {
+            const prev = nodeToRemove.previousSibling;
+            nodeToRemove.parentNode?.removeChild(nodeToRemove);
+            nodeToRemove = prev;
+        }
+        previous.parentNode?.removeChild(previous);
+
+        // Remove the ZWS from the cursor's text node
+        if (container.textContent?.replace(zeroWidthSpace, '') === '') {
+            // Text node is only ZWS — remove it entirely
+            const nextSibling = container.nextSibling;
+            const parentNode = container.parentNode;
+            container.parentNode?.removeChild(container);
+            // Place cursor at end of previous text node
+            const prevText = parentNode?.lastChild;
+            if (prevText && prevText.nodeType === 3) {
+                const newRange = document.createRange();
+                newRange.setStart(prevText, prevText.textContent?.length || 0);
+                newRange.collapse(true);
+                selection.removeAllRanges();
+                selection.addRange(newRange);
+            }
+        }
+
+        return true;
+    }
+
+    private defaultOnEnter(element: HTMLElement, selection: Selection, _editor: any): boolean {
+        const range = selection.getRangeAt(0);
+        const container = range.startContainer;
+        const offset = range.startOffset;
+
+        // Detect empty line: cursor is at a position where the
+        // previous sibling is a <br> and there's no text after it
+        const zeroWidthSpace = /\u200B/g;
+        let lineIsEmpty = false;
+
+        if (container.nodeType === 3) {
+            const textBefore = (container.textContent || '').slice(0, offset).replace(zeroWidthSpace, '').trim();
+            const textAfter = (container.textContent || '').slice(offset).replace(zeroWidthSpace, '').trim();
+            if (textBefore === '' && textAfter === '') {
+                // Walk back past empty text nodes to find a <br>
+                let previous: Node | null = container.previousSibling;
+                while (previous && previous.nodeType === 3
+                    && (previous.textContent || '').replace(zeroWidthSpace, '').trim() === '') {
+                    previous = previous.previousSibling;
+                }
+                if (previous && previous.nodeType === 1 && (previous as HTMLElement).tagName === 'BR') {
+                    lineIsEmpty = true;
+                }
+            }
+        } else if (container.nodeType === 1) {
+            const childAtCursor = (container as HTMLElement).childNodes[offset - 1];
+            if (childAtCursor && childAtCursor.nodeType === 1 && (childAtCursor as HTMLElement).tagName === 'BR') {
+                // Only treat as empty line if there's real content before
+                // the <br> — an empty paragraph's placeholder <br> doesn't count
+                const textBefore = Array.from((container as HTMLElement).childNodes)
+                    .slice(0, offset - 1)
+                    .map(node => node.textContent || '')
+                    .join('')
+                    .replace(zeroWidthSpace, '')
+                    .trim();
+                const textAfter = Array.from((container as HTMLElement).childNodes)
+                    .slice(offset)
+                    .map(node => node.textContent || '')
+                    .join('')
+                    .replace(zeroWidthSpace, '')
+                    .trim();
+                if (textAfter === '' && textBefore !== '') {
+                    lineIsEmpty = true;
+                }
+            }
+        }
+
+        if (lineIsEmpty) {
+            // Double Enter: remove the trailing <br>, any empty text
+            // nodes after it, and the cursor's text node
+            let nodeToRemove: Node | null = container.nodeType === 3
+                ? container.previousSibling
+                : (container as HTMLElement).childNodes[offset - 1];
+            // Walk past empty text nodes to find the <br>
+            while (nodeToRemove && nodeToRemove.nodeType === 3
+                && (nodeToRemove.textContent || '').replace(zeroWidthSpace, '').trim() === '') {
+                const previous = nodeToRemove.previousSibling;
+                nodeToRemove.parentNode?.removeChild(nodeToRemove);
+                nodeToRemove = previous;
+            }
+            // Remove the <br> itself
+            if (nodeToRemove && nodeToRemove.nodeType === 1
+                && (nodeToRemove as HTMLElement).tagName === 'BR') {
+                nodeToRemove.parentNode?.removeChild(nodeToRemove);
+            }
+            // Remove the cursor's empty text node
+            if (container.nodeType === 3
+                && container.textContent?.replace(zeroWidthSpace, '').trim() === '') {
+                container.parentNode?.removeChild(container);
+            }
+
+            const newParagraph = document.createElement('p');
+            newParagraph.innerHTML = '<br>';
+            // Find the top-level block to insert after
+            let block: Node = element;
+            while (block.parentNode && block.parentNode !== _editor.element) {
+                block = block.parentNode;
+            }
+            (block as HTMLElement).after(newParagraph);
+            const newRange = document.createRange();
+            newRange.setStart(newParagraph, 0);
+            newRange.collapse(true);
+            selection.removeAllRanges();
+            selection.addRange(newRange);
+        } else {
+            // Single Enter: insert <br> followed by a zero-width space.
+            // The ZWS gives the browser a text node to place the cursor
+            // in — without it, Firefox removes the <br> when the user
+            // types the next character.
+            const brElement = document.createElement('br');
+            const cursorAnchor = document.createTextNode('\u200B');
+            range.deleteContents();
+            range.insertNode(cursorAnchor);
+            range.insertNode(brElement);
+            const newRange = document.createRange();
+            newRange.setStart(cursorAnchor, 1);
+            newRange.collapse(true);
+            selection.removeAllRanges();
+            selection.addRange(newRange);
+        }
+        return true;
+    }
+}
+
 /**
  * Fenced code blocks: lines between ``` delimiters become <pre><code>.
  *
  *   converter.toHTML('```js\nlet x = 1;\n```')
  *   // <pre><code class="language-js">let x = 1;</code></pre>
  */
-class FencedCodeTag implements Tag {
+class FencedCodeTag extends BaseTag implements Tag {
     name = 'fencedCode';
     selector = 'PRE';
     button = {
@@ -192,7 +398,7 @@ class FencedCodeTag implements Tag {
  *
  *   converter.toHTML('---')  // '<hr>'
  */
-class HorizontalRuleTag implements Tag {
+class HorizontalRuleTag extends BaseTag implements Tag {
     name = 'hr';
     selector = 'HR';
     button = {
@@ -229,9 +435,12 @@ class HorizontalRuleTag implements Tag {
  *
  *   converter.toHTML('## Hello')  // <h2 id='Hello'>Hello</h2>
  */
-class HeadingTag implements Tag {
+class HeadingTag extends BaseTag implements Tag {
     name = 'heading';
     selector = 'H1,H2,H3,H4,H5,H6';
+    eventHandlers = {
+        'onEnter': this.onEnter,
+    };
     button = {
         show: false,
         label: 'Heading',
@@ -287,6 +496,22 @@ class HeadingTag implements Tag {
      * Generate a PascalCase anchor ID from heading text so that
      * in-page links like #MyHeading work without manual IDs.
      */
+    /**
+     * Headings always exit on Enter — you don't continue a heading
+     * across multiple lines.
+     */
+    private onEnter(heading: HTMLElement, selection: Selection, _editor: any): boolean {
+        const newParagraph = document.createElement('p');
+        newParagraph.innerHTML = '<br>';
+        heading.after(newParagraph);
+        const range = document.createRange();
+        range.setStart(newParagraph, 0);
+        range.collapse(true);
+        selection.removeAllRanges();
+        selection.addRange(range);
+        return true;
+    }
+
     private anchorId(text: string): string {
         return text.trim().split(/\s+/).map(word =>
             word.charAt(0).toUpperCase() + word.slice(1).toLowerCase()
@@ -301,7 +526,7 @@ class HeadingTag implements Tag {
  *   converter.toHTML('> hello\n> world')
  *   // <blockquote><p>hello\nworld</p></blockquote>
  */
-class BlockquoteTag implements Tag {
+class BlockquoteTag extends BaseTag implements Tag {
     name = 'blockquote';
     selector = 'BLOCKQUOTE';
     button = {
@@ -311,6 +536,9 @@ class BlockquoteTag implements Tag {
     };
     template = '> Quote\n> continues here';
     replaceSelection = true;
+    eventHandlers = {
+        'onEnter': this.onEnter,
+    };
 
     match(context: MatchContext): SourceToken | null {
         const quotePrefix = /^>\s?/;
@@ -330,12 +558,153 @@ class BlockquoteTag implements Tag {
     }
 
     toHTML(token: SourceToken, convert: Converter): string {
-        return '<blockquote>' + convert.block(token.content) + '</blockquote>';
+        // Within a blockquote, consecutive lines without a blank line
+        // between them should produce <br> line breaks (not merge into
+        // one paragraph). Insert hard break markers before block parsing
+        // so the inline processor creates <br> elements.
+        const withHardBreaks = token.content.replace(
+            /([^\n])\n(?!\n)/g,  // \n not followed by another \n
+            '$1  \n'             // trailing two spaces = hard break
+        );
+        return '<blockquote>' + convert.block(withHardBreaks) + '</blockquote>';
     }
 
     toMarkdown(element: HTMLElement, convert: Converter): string {
-        const lines = convert.children(element).trim().split('\n');
-        return '\n\n' + lines.map(line => '> ' + line).join('\n') + '\n\n';
+        // Each <p> inside the blockquote is a paragraph group.
+        // Within a <p>, <br> elements create line breaks.
+        // Separate paragraphs get a blank > line between them.
+        const paragraphs: string[] = [];
+        for (const child of Array.from(element.childNodes)) {
+            if (child.nodeType === 1 && (child as HTMLElement).tagName === 'P') {
+                const lines = this.paragraphToLines(child as HTMLElement, convert);
+                paragraphs.push(lines.map(line => '> ' + line).join('\n'));
+            } else {
+                const text = convert.node(child).trim();
+                if (text) {
+                    paragraphs.push('> ' + text);
+                }
+            }
+        }
+        return '\n\n' + paragraphs.join('\n>\n') + '\n\n';
+    }
+
+    /**
+     * Split a paragraph's content into lines at <br> elements.
+     */
+    private paragraphToLines(paragraph: HTMLElement, convert: Converter): string[] {
+        const lines: string[] = [];
+        let currentLine = '';
+        for (const child of Array.from(paragraph.childNodes)) {
+            if (child.nodeType === 1 && (child as HTMLElement).tagName === 'BR') {
+                lines.push(currentLine);
+                currentLine = '';
+            } else {
+                currentLine += convert.node(child);
+            }
+        }
+        if (currentLine.trim()) {
+            lines.push(currentLine);
+        }
+        return lines;
+    }
+
+    /**
+     * Enter inside a blockquote adds a new paragraph within the quote.
+     * Double-Enter (empty line) exits the blockquote and creates a
+     * new paragraph after it — matching the behavior users expect
+     * from list editing.
+     */
+    private onEnter(blockquote: HTMLElement, selection: Selection, _editor: any): boolean {
+        // Find the text content after the cursor to determine if
+        // the current line is empty (for double-Enter exit detection)
+        const range = selection.getRangeAt(0);
+        const container = range.startContainer;
+        const offset = range.startOffset;
+
+        // Check if the cursor is at an empty line: either the entire
+        // paragraph is empty, or the cursor is right after a <br> with
+        // nothing after it
+        let lineIsEmpty = false;
+        const paragraph = container.nodeType === 1
+            ? container as HTMLElement
+            : container.parentElement;
+
+        if (paragraph) {
+            const zeroWidthSpace = /\u200B/g;
+            const textAfterCursor = container.nodeType === 3
+                ? (container.textContent || '').slice(offset).replace(zeroWidthSpace, '').trim()
+                : '';
+            const textBeforeCursor = container.nodeType === 3
+                ? (container.textContent || '').slice(0, offset).replace(zeroWidthSpace, '').trim()
+                : '';
+
+            // Empty if: whole paragraph is empty, or cursor is at the
+            // start of an empty text node after a <br>
+            const fullText = paragraph.textContent?.replace(zeroWidthSpace, '').trim() || '';
+            if (fullText === '') {
+                lineIsEmpty = true;
+            } else if (textBeforeCursor === '' && textAfterCursor === '') {
+                // Walk back past empty text nodes to find a <br>
+                let previous: Node | null = container.nodeType === 3
+                    ? container.previousSibling
+                    : (container as HTMLElement).childNodes[offset - 1];
+                while (previous && previous.nodeType === 3
+                    && (previous.textContent || '').replace(zeroWidthSpace, '').trim() === '') {
+                    previous = previous.previousSibling;
+                }
+                if (previous && previous.nodeType === 1 && (previous as HTMLElement).tagName === 'BR') {
+                    lineIsEmpty = true;
+                }
+            }
+        }
+
+        if (lineIsEmpty) {
+            // Double-Enter: clean up the trailing <br> and empty nodes,
+            // then exit the blockquote
+            const lastParagraph = blockquote.querySelector('p:last-child');
+            if (lastParagraph) {
+                // Remove trailing <br> and empty text nodes
+                const zwsPattern = /\u200B/g;
+                while (lastParagraph.lastChild) {
+                    const child = lastParagraph.lastChild;
+                    if (child.nodeType === 1 && (child as HTMLElement).tagName === 'BR') {
+                        child.remove();
+                        break;
+                    }
+                    if (child.nodeType === 3
+                        && (child.textContent || '').replace(zwsPattern, '').trim() === '') {
+                        child.remove();
+                        continue;
+                    }
+                    break;
+                }
+                // If the paragraph is now empty, remove it entirely
+                if (lastParagraph.textContent?.replace(zwsPattern, '').trim() === '') {
+                    lastParagraph.remove();
+                }
+            }
+            const newParagraph = document.createElement('p');
+            newParagraph.innerHTML = '<br>';
+            blockquote.after(newParagraph);
+            const newRange = document.createRange();
+            newRange.setStart(newParagraph, 0);
+            newRange.collapse(true);
+            selection.removeAllRanges();
+            selection.addRange(newRange);
+        } else {
+            // Single Enter: insert <br> + ZWS cursor anchor
+            const brElement = document.createElement('br');
+            const cursorAnchor = document.createTextNode('\u200B');
+            range.deleteContents();
+            range.insertNode(cursorAnchor);
+            range.insertNode(brElement);
+            const newRange = document.createRange();
+            newRange.setStart(cursorAnchor, 1);
+            newRange.collapse(true);
+            selection.removeAllRanges();
+            selection.addRange(newRange);
+        }
+        return true;
     }
 }
 
@@ -345,9 +714,12 @@ class BlockquoteTag implements Tag {
  *
  *   converter.toHTML('- one\n- two\n  1. nested')
  */
-class ListTag implements Tag {
+class ListTag extends BaseTag implements Tag {
     name = 'list';
     selector = 'UL,OL';
+    eventHandlers = {
+        'onEnter': this.onEnter,
+    };
     button = {
         show: false,
         label: 'List',
@@ -387,6 +759,129 @@ class ListTag implements Tag {
      * Count how many consecutive lines belong to this list, including
      * nested sublists (detected by increased indentation).
      */
+    /**
+     * List Enter behavior has three tiers:
+     * 1. Single Enter → <br> within current <li> (line continuation)
+     * 2. Double Enter in non-empty <li> → new <li> sibling
+     * 3. Double Enter in empty <li> → exit list, create <p> after it
+     */
+    private onEnter(listElement: HTMLElement, selection: Selection, _editor: any): boolean {
+        // Find the <li> containing the cursor
+        let listItem: HTMLElement | null = null;
+        let node: Node | null = selection.anchorNode;
+        while (node && node !== listElement) {
+            if (node.nodeType === 1 && (node as HTMLElement).tagName === 'LI') {
+                listItem = node as HTMLElement;
+                break;
+            }
+            node = node.parentNode;
+        }
+        if (!listItem) {
+            return false;
+        }
+
+        const zeroWidthSpace = /\u200B/g;
+        const itemText = (listItem.textContent || '').replace(zeroWidthSpace, '').trim();
+        const range = selection.getRangeAt(0);
+        const container = range.startContainer;
+        const offset = range.startOffset;
+
+        // Detect empty line after <br> (same logic as defaultOnEnter)
+        let lineIsEmpty = false;
+        if (container.nodeType === 3) {
+            const textBefore = (container.textContent || '').slice(0, offset).replace(zeroWidthSpace, '').trim();
+            const textAfter = (container.textContent || '').slice(offset).replace(zeroWidthSpace, '').trim();
+            if (textBefore === '' && textAfter === '') {
+                let previous: Node | null = container.previousSibling;
+                while (previous && previous.nodeType === 3
+                    && (previous.textContent || '').replace(zeroWidthSpace, '').trim() === '') {
+                    previous = previous.previousSibling;
+                }
+                if (previous && previous.nodeType === 1 && (previous as HTMLElement).tagName === 'BR') {
+                    lineIsEmpty = true;
+                }
+            }
+        } else if (container.nodeType === 1) {
+            const childAtCursor = (container as HTMLElement).childNodes[offset - 1];
+            if (childAtCursor && childAtCursor.nodeType === 1 && (childAtCursor as HTMLElement).tagName === 'BR') {
+                const textBefore = Array.from((container as HTMLElement).childNodes)
+                    .slice(0, offset - 1)
+                    .map(child => child.textContent || '')
+                    .join('')
+                    .replace(zeroWidthSpace, '')
+                    .trim();
+                const textAfter = Array.from((container as HTMLElement).childNodes)
+                    .slice(offset)
+                    .map(child => child.textContent || '')
+                    .join('')
+                    .replace(zeroWidthSpace, '')
+                    .trim();
+                if (textAfter === '' && textBefore !== '') {
+                    lineIsEmpty = true;
+                }
+            }
+        }
+
+        if (lineIsEmpty && itemText === '') {
+            // Tier 3: empty <li> — exit the list
+            listItem.remove();
+            const newParagraph = document.createElement('p');
+            newParagraph.innerHTML = '<br>';
+            listElement.after(newParagraph);
+            const newRange = document.createRange();
+            newRange.setStart(newParagraph, 0);
+            newRange.collapse(true);
+            selection.removeAllRanges();
+            selection.addRange(newRange);
+            return true;
+        }
+
+        if (lineIsEmpty) {
+            // Tier 2: non-empty <li> with empty line — create new <li>
+            // Remove the trailing <br> and empty nodes
+            let nodeToRemove: Node | null = container.nodeType === 3
+                ? container.previousSibling
+                : (container as HTMLElement).childNodes[offset - 1];
+            while (nodeToRemove && nodeToRemove.nodeType === 3
+                && (nodeToRemove.textContent || '').replace(zeroWidthSpace, '').trim() === '') {
+                const previous = nodeToRemove.previousSibling;
+                nodeToRemove.parentNode?.removeChild(nodeToRemove);
+                nodeToRemove = previous;
+            }
+            if (nodeToRemove && nodeToRemove.nodeType === 1
+                && (nodeToRemove as HTMLElement).tagName === 'BR') {
+                nodeToRemove.parentNode?.removeChild(nodeToRemove);
+            }
+            if (container.nodeType === 3
+                && container.textContent?.replace(zeroWidthSpace, '').trim() === '') {
+                container.parentNode?.removeChild(container);
+            }
+
+            const newItem = document.createElement('li');
+            newItem.innerHTML = '<br>';
+            listItem.after(newItem);
+            const newRange = document.createRange();
+            newRange.setStart(newItem, 0);
+            newRange.collapse(true);
+            selection.removeAllRanges();
+            selection.addRange(newRange);
+            return true;
+        }
+
+        // Tier 1: single Enter — insert <br> + ZWS cursor anchor
+        const brElement = document.createElement('br');
+        const cursorAnchor = document.createTextNode('\u200B');
+        range.deleteContents();
+        range.insertNode(cursorAnchor);
+        range.insertNode(brElement);
+        const newRange = document.createRange();
+        newRange.setStart(cursorAnchor, 1);
+        newRange.collapse(true);
+        selection.removeAllRanges();
+        selection.addRange(newRange);
+        return true;
+    }
+
     private countListLines(lines: string[], start: number): number {
         const indentedUnordered = /^(\s*)[*\-+]\s/;
         const indentedOrdered = /^(\s*)\d+\.\s/;
@@ -501,7 +996,7 @@ class ListTag implements Tag {
  *
  *   converter.toHTML('| A | B |\n|---|---|\n| 1 | 2 |')
  */
-class TableTag implements Tag {
+class TableTag extends BaseTag implements Tag {
     name = 'table';
     selector = 'TABLE';
     button = {
@@ -611,7 +1106,7 @@ class TableTag implements Tag {
  *
  *   converter.toHTML('hello world')  // '<p>hello world</p>'
  */
-class ParagraphTag implements Tag {
+class ParagraphTag extends BaseTag implements Tag {
     name = 'paragraph';
     selector = 'P';
 

src/ts/tokenizer.ts

@@ -50,7 +50,7 @@ export interface DelimiterDef {
  * and followed by non-whitespace. Right-flanking is the reverse.
  */
 const PUNCTUATION = new Set(
-    ' \t\n.,;:!?\'"()[]{}/<>\\-~#@&^|*`_'.split('')
+    ' \t\n\u00A0.,;:!?\'"()[]{}/<>\\-~#@&^|*`_'.split('')
 );
 
 /**
@@ -416,9 +416,9 @@ export class InlineTokenizer {
             const charAfter = source[position + delimiter.length];
 
             const leftFlanking = (charBefore === undefined || PUNCTUATION.has(charBefore) || charBefore === '\n')
-                && charAfter !== undefined && charAfter !== ' ' && charAfter !== '\n' && charAfter !== '\t';
+                && charAfter !== undefined && charAfter !== ' ' && charAfter !== '\n' && charAfter !== '\t' && charAfter !== '\u00A0';
 
-            const rightFlanking = charBefore !== undefined && charBefore !== ' ' && charBefore !== '\n' && charBefore !== '\t'
+            const rightFlanking = charBefore !== undefined && charBefore !== ' ' && charBefore !== '\n' && charBefore !== '\t' && charBefore !== '\u00A0'
                 && (charAfter === undefined || PUNCTUATION.has(charAfter) || charAfter === '\n');
 
             if (leftFlanking) {

src/ts/types.ts

@@ -70,6 +70,13 @@ export interface Tag {
     template?: string;
     replaceSelection?: boolean;
     button?: ToolbarButton;
+    /** Keyboard event handlers for WYSIWYG mode. Keys are event names
+     *  like 'onEnter', 'onBackspace', 'onTab'. The handler receives
+     *  the tag's element, the current selection, and the editor instance. */
+    eventHandlers?: Record<string, (element: HTMLElement, selection: Selection, editor: any) => boolean>;
+    /** Dispatch a keydown event to the appropriate handler in
+     *  eventHandlers. Provided by BaseTag; override for custom logic. */
+    handleKeydown?: (element: HTMLElement, event: KeyboardEvent, selection: Selection, editor: any) => boolean;
 }
 
 /**

test/hopdown.test.ts

@@ -534,3 +534,18 @@ describe('Backslash-escaped HTML tags', () => {
         expect(rehtml).toBe(rehtml2);
     });
 });
+
+describe('Table cell round-trip', () => {
+    it('inline formatting in cells survives round-trip', () => {
+        const html = '<table><thead><tr><th>A</th><th>B</th></tr></thead><tbody><tr><td><strong>bold</strong></td><td><em>italic</em></td></tr></tbody></table>';
+        expect(H(M(html))).toBe(html);
+    });
+    it('code in cells survives round-trip', () => {
+        const html = '<table><thead><tr><th>A</th></tr></thead><tbody><tr><td><code>x</code></td></tr></tbody></table>';
+        expect(H(M(html))).toBe(html);
+    });
+    it('literal * in cells survives round-trip', () => {
+        const html = '<table><thead><tr><th>A</th></tr></thead><tbody><tr><td>2 * 3</td></tr></tbody></table>';
+        expect(H(M(html))).toBe(html);
+    });
+});

test/integration/dev-server.js

@@ -0,0 +1,106 @@
+/**
+ * Development server with livereload.
+ *
+ * Serves the test page and ribbit dist files. Watches src/ for
+ * changes, rebuilds automatically, and notifies connected browsers
+ * to reload via a simple EventSource stream.
+ *
+ * Run: npm run dev
+ */
+const { createServer } = require('./server');
+const { execSync } = require('child_process');
+const fs = require('fs');
+const path = require('path');
+
+const PORT = 8080;
+const WATCH_DIRS = [
+    path.join(__dirname, '..', '..', 'src'),
+    path.join(__dirname, '..', '..', 'test', 'integration'),
+];
+const DEBOUNCE_MS = 300;
+
+const server = createServer(PORT);
+const reloadClients = [];
+
+// Patch the server to add the livereload endpoint
+const originalServer = require('http').createServer;
+const httpServer = server._server || (() => {
+    // Access the internal server by starting and intercepting
+    let captured = null;
+    const origListen = require('http').Server.prototype.listen;
+    require('http').Server.prototype.listen = function (...args) {
+        captured = this;
+        return origListen.apply(this, args);
+    };
+    server.start();
+    require('http').Server.prototype.listen = origListen;
+    return captured;
+})();
+
+// Simpler approach: create a standalone livereload server
+const reloadServer = require('http').createServer((request, response) => {
+    response.writeHead(200, {
+        'Content-Type': 'text/event-stream',
+        'Cache-Control': 'no-cache',
+        'Connection': 'keep-alive',
+        'Access-Control-Allow-Origin': '*',
+    });
+    reloadClients.push(response);
+    request.on('close', () => {
+        const index = reloadClients.indexOf(response);
+        if (index >= 0) {
+            reloadClients.splice(index, 1);
+        }
+    });
+});
+
+function notifyReload() {
+    for (const client of reloadClients) {
+        client.write('data: reload\n\n');
+    }
+}
+
+function rebuild() {
+    try {
+        console.log('\n🔨 Rebuilding...');
+        execSync('npm run build:js && npm run build:css', {
+            cwd: path.join(__dirname, '..', '..'),
+            stdio: 'pipe',
+        });
+        console.log('✅ Build complete');
+        notifyReload();
+    } catch (error) {
+        console.error('❌ Build failed:', error.stderr?.toString().slice(0, 500));
+    }
+}
+
+let debounceTimer = null;
+function onFileChange(filename) {
+    if (debounceTimer) {
+        clearTimeout(debounceTimer);
+    }
+    console.log(`📝 Changed: ${filename}`);
+    debounceTimer = setTimeout(rebuild, DEBOUNCE_MS);
+}
+
+// Watch source directories
+for (const directory of WATCH_DIRS) {
+    if (fs.existsSync(directory)) {
+        fs.watch(directory, { recursive: true }, (eventType, filename) => {
+            if (filename && !filename.includes('node_modules')) {
+                onFileChange(filename);
+            }
+        });
+    }
+}
+
+server.start().then(() => {
+    reloadServer.listen(PORT + 1, () => {
+        console.log(`\n🐸 Ribbit dev server`);
+        console.log(`   Editor:     http://localhost:${PORT}`);
+        console.log(`   Livereload: http://localhost:${PORT + 1} (EventSource)`);
+        console.log(`   Watching:   src/, test/integration/`);
+        console.log(`\n   Add this to the page to enable livereload:`);
+        console.log(`   <script>new EventSource('http://localhost:${PORT + 1}').onmessage = () => location.reload()</script>\n`);
+    });
+});

test/integration/index.html

@@ -42,5 +42,10 @@
         editor.run();
         window.__ribbitEditor = editor;
     </script>
+    <script>
+        // Livereload — connects to dev server's EventSource endpoint.
+        // Silently fails if the dev server isn't running.
+        try { new EventSource('http://localhost:8081').onmessage = () => location.reload(); } catch(e) {}
+    </script>
 </body>
 </html>

test/integration/test_wysiwyg.js

@@ -318,6 +318,67 @@ async function runTests() {
         assert(html.includes('<blockquote'), `No blockquote after "> ": ${html}`);
     });
 
+    await test('enter inside blockquote adds new line', async () => {
+        await resetEditor();
+        await typeString('> first line');
+        let html = await getHTML();
+        assert(html.includes('<blockquote'), `No blockquote: ${html}`);
+
+        await typeChar(Key.ENTER);
+        await typeString('second line');
+        html = await getHTML();
+
+        // Both lines must be inside the same blockquote
+        const blockquoteCount = (html.match(/<blockquote/g) || []).length;
+        assert(blockquoteCount === 1, `Expected 1 blockquote, got ${blockquoteCount}: ${html}`);
+        assert(html.includes('first line'), `Missing first line: ${html}`);
+        assert(html.includes('second line'), `Missing second line: ${html}`);
+        // The two lines must be separate — not merged into one string
+        assert(!html.includes('first linesecond'), `Lines merged without break: ${html}`);
+
+        // Markdown should be "> foo\n> bar" — continuation, no blank lines
+        const markdown = await getMarkdown();
+        assert(markdown.includes('> first line'), `Missing > first line in markdown: ${markdown}`);
+        assert(markdown.includes('> second line'), `Missing > second line in markdown: ${markdown}`);
+        assert(!markdown.includes('>\n>'), `Unwanted blank > line in markdown: ${markdown}`);
+    });
+
+    await test('blockquote paragraphs survive mode round-trip', async () => {
+        await resetEditor();
+        await typeString('> foo');
+        await typeChar(Key.ENTER);
+        await typeString('bar');
+        await driver.sleep(50);
+
+        // Switch to source and back to wysiwyg twice
+        await driver.executeScript('window.__ribbitEditor.edit()');
+        await driver.sleep(50);
+        await driver.executeScript('window.__ribbitEditor.wysiwyg()');
+        await driver.sleep(50);
+        await driver.executeScript('window.__ribbitEditor.edit()');
+        await driver.sleep(50);
+
+        const markdown = await driver.executeScript('return document.getElementById("ribbit").textContent');
+        assert(markdown.includes('> foo'), `Missing > foo: ${markdown}`);
+        assert(markdown.includes('> bar'), `Missing > bar — second line lost its prefix: ${markdown}`);
+    });
+
+    await test('double enter exits blockquote', async () => {
+        await resetEditor();
+        await typeString('> quoted');
+        await typeChar(Key.ENTER);
+        await typeChar(Key.ENTER);
+        await typeString('after');
+        const html = await getHTML();
+        assert(html.includes('<blockquote'), `No blockquote: ${html}`);
+        assert(html.includes('quoted'), `Missing quoted text: ${html}`);
+        assert(html.includes('after'), `Missing text after blockquote: ${html}`);
+        // "after" should NOT be inside the blockquote
+        const afterBlockquote = html.indexOf('</blockquote');
+        const afterText = html.indexOf('after');
+        assert(afterText > afterBlockquote, `"after" is inside blockquote: ${html}`);
+    });
+
     // ── Horizontal rule ──
 
     console.log('  Horizontal rule:');
@@ -412,6 +473,99 @@ async function runTests() {
         assert(!html.includes('data-speculative'), `Speculative not closed: ${html}`);
     });
 
+    console.log('  Enter behavior:');
+
+    await test('block pattern after Enter splits and transforms', async () => {
+        await resetEditor();
+        await typeString('foo');
+        await typeChar(Key.ENTER);
+        await typeString('> bar');
+        await driver.sleep(50);
+        const html = await getHTML();
+        assert(html.includes('<blockquote'), `> after Enter did not create blockquote: ${html}`);
+        assert(html.includes('foo'), `Lost content before split: ${html}`);
+        assert(html.includes('bar'), `Lost content after split: ${html}`);
+    });
+
+    await test('single Enter in paragraph inserts line break', async () => {
+        await resetEditor();
+        await typeString('line one');
+        await typeChar(Key.ENTER);
+        await typeString('line two');
+        const markdown = await getMarkdown();
+        // Single Enter = one \n, not \n\n
+        assert(markdown.includes('line one'), `Missing line one: ${markdown}`);
+        assert(markdown.includes('line two'), `Missing line two: ${markdown}`);
+        assert(!markdown.includes('line one\n\nline two'), `Got paragraph break instead of line break: ${markdown}`);
+    });
+
+    await test('double Enter in paragraph creates new block', async () => {
+        await resetEditor();
+        await typeString('first paragraph');
+        await typeChar(Key.ENTER);
+        await typeChar(Key.ENTER);
+        await typeString('second paragraph');
+        const html = await getHTML();
+        // Double Enter = new <p>, so two separate paragraphs
+        const paragraphCount = (html.match(/<p[\s>]/g) || []).length;
+        assert(paragraphCount >= 2, `Expected 2+ paragraphs, got ${paragraphCount}: ${html}`);
+    });
+
+    await test('backspace at start of line after Enter joins lines', async () => {
+        await resetEditor();
+        await typeString('foo');
+        await typeChar(Key.ENTER);
+        await typeChar(Key.BACK_SPACE);
+        await driver.sleep(50);
+        const html = await getHTML();
+        // The <br> should be removed, cursor at end of "foo"
+        assert(!html.includes('<br'), `<br> not removed: ${html}`);
+        assert(html.includes('foo'), `Content lost: ${html}`);
+    });
+
+    await test('single Enter in list item inserts line break', async () => {
+        await resetEditor();
+        await typeString('- line one');
+        await typeChar(Key.ENTER);
+        await typeString('line two');
+        const markdown = await getMarkdown();
+        // Both lines in the same list item
+        assert(markdown.includes('- line one'), `Missing list marker: ${markdown}`);
+        assert(markdown.includes('line two'), `Missing line two: ${markdown}`);
+        // Should NOT create a second list item
+        const markerCount = (markdown.match(/^- /gm) || []).length;
+        assert(markerCount === 1, `Expected 1 list marker, got ${markerCount}: ${markdown}`);
+    });
+
+    await test('double Enter in list item creates new item', async () => {
+        await resetEditor();
+        await typeString('- first');
+        await typeChar(Key.ENTER);
+        await typeChar(Key.ENTER);
+        await typeString('second');
+        const markdown = await getMarkdown();
+        const markerCount = (markdown.match(/^- /gm) || []).length;
+        assert(markerCount === 2, `Expected 2 list markers, got ${markerCount}: ${markdown}`);
+        assert(markdown.includes('- first'), `Missing first item: ${markdown}`);
+        assert(markdown.includes('- second'), `Missing second item: ${markdown}`);
+    });
+
+    await test('double Enter on empty list item exits list', async () => {
+        await resetEditor();
+        await typeString('- item');
+        await typeChar(Key.ENTER);
+        await typeChar(Key.ENTER);
+        await typeChar(Key.ENTER);
+        await typeChar(Key.ENTER);
+        await typeString('after list');
+        const html = await getHTML();
+        assert(html.includes('after list'), `Missing text after list: ${html}`);
+        // "after list" should NOT be inside the <ul>
+        const ulEnd = html.indexOf('</ul>');
+        const afterPos = html.indexOf('after list');
+        assert(afterPos > ulEnd, `"after list" is inside the list: ${html}`);
+    });
+
     // ── Complex document ──
 
     console.log('  Complex document:');
@@ -422,6 +576,7 @@ async function runTests() {
         await typeChar(Key.ENTER);
         await typeString('Some **bold** text.');
         await typeChar(Key.ENTER);
+        await typeChar(Key.ENTER);
         await typeString('## Section');
         await typeChar(Key.ENTER);
         await typeString('- item one');
@@ -474,6 +629,32 @@ async function runTests() {
         assert(html.includes('<ul') || html.includes('<li'), `No list after "+ ": ${html}`);
     });
 
+    console.log('  Underscore emphasis:');
+
+    await test('_text_ transforms to italic (shows * delimiters)', async () => {
+        await resetEditor();
+        await typeString('_hello_');
+        const html = await getHTML();
+        assert(html.includes('<em'), `No <em> after _hello_: ${html}`);
+        assert(!html.includes('data-speculative'), `Still speculative: ${html}`);
+    });
+
+    await test('_text shows speculative italic', async () => {
+        await resetEditor();
+        await typeString('_hel');
+        const html = await getHTML();
+        assert(html.includes('<em'), `No <em> after _hel: ${html}`);
+        assert(html.includes('data-speculative'), `Not speculative: ${html}`);
+    });
+
+    await test('__text__ transforms to bold', async () => {
+        await resetEditor();
+        await typeString('__hello__');
+        const html = await getHTML();
+        assert(html.includes('<strong'), `No <strong> after __hello__: ${html}`);
+        assert(!html.includes('data-speculative'), `Still speculative: ${html}`);
+    });
+
     console.log('  Backslash escapes:');
 
     await test('backslash is just a character in WYSIWYG', async () => {