feat: columns

apps/client/public/locales/en-US/translation.json

@@ -363,6 +363,15 @@
   "Heading {{level}}": "Heading {{level}}",
   "Toggle title": "Toggle title",
   "Write anything. Enter \"/\" for commands": "Write anything. Enter \"/\" for commands",
+  "Write...": "Write...",
+  "Column count": "Column count",
+  "{{count}} Columns": "{{count}} Columns",
+  "Equal columns": "Equal columns",
+  "Left sidebar": "Left sidebar",
+  "Right sidebar": "Right sidebar",
+  "Wide center": "Wide center",
+  "Left wide": "Left wide",
+  "Right wide": "Right wide",
   "Names do not match": "Names do not match",
   "Today, {{time}}": "Today, {{time}}",
   "Yesterday, {{time}}": "Yesterday, {{time}}",

apps/client/src/components/icons/icon-columns-4.tsx

@@ -0,0 +1,27 @@
+import { rem } from "@mantine/core";
+
+type Props = {
+  size?: number | string;
+  stroke?: number;
+};
+
+export function IconColumns4({ size = 24, stroke = 2 }: Props) {
+  return (
+    <svg
+      xmlns="http://www.w3.org/2000/svg"
+      width={rem(size)}
+      height={rem(size)}
+      viewBox="0 0 24 24"
+      fill="none"
+      stroke="currentColor"
+      strokeWidth={stroke}
+      strokeLinecap="round"
+      strokeLinejoin="round"
+    >
+      <path d="M3 4a1 1 0 0 1 1 -1h16a1 1 0 0 1 1 1v16a1 1 0 0 1 -1 1h-16a1 1 0 0 1 -1 -1v-16" />
+      <path d="M7.5 3v18" />
+      <path d="M12 3v18" />
+      <path d="M16.5 3v18" />
+    </svg>
+  );
+}

apps/client/src/components/icons/icon-columns-5.tsx

@@ -0,0 +1,28 @@
+import { rem } from "@mantine/core";
+
+type Props = {
+  size?: number | string;
+  stroke?: number;
+};
+
+export function IconColumns5({ size = 24, stroke = 2 }: Props) {
+  return (
+    <svg
+      xmlns="http://www.w3.org/2000/svg"
+      width={rem(size)}
+      height={rem(size)}
+      viewBox="0 0 24 24"
+      fill="none"
+      stroke="currentColor"
+      strokeWidth={stroke}
+      strokeLinecap="round"
+      strokeLinejoin="round"
+    >
+      <path d="M3 4a1 1 0 0 1 1 -1h16a1 1 0 0 1 1 1v16a1 1 0 0 1 -1 1h-16a1 1 0 0 1 -1 -1v-16" />
+      <path d="M6.6 3v18" />
+      <path d="M10.2 3v18" />
+      <path d="M13.8 3v18" />
+      <path d="M17.4 3v18" />
+    </svg>
+  );
+}

apps/client/src/features/editor/components/columns/columns-menu.tsx

@@ -0,0 +1,255 @@
+import { BubbleMenu as BaseBubbleMenu } from "@tiptap/react/menus";
+import { findParentNode, posToDOMRect, useEditorState } from "@tiptap/react";
+import React, { useCallback, useState } from "react";
+import { Node as PMNode } from "prosemirror-model";
+import {
+  EditorMenuProps,
+  ShouldShowProps,
+} from "@/features/editor/components/table/types/types.ts";
+import { ActionIcon, Tooltip, Popover, Button } from "@mantine/core";
+import clsx from "clsx";
+import {
+  IconChevronDown,
+  IconCheck,
+  IconColumns2,
+  IconColumns3,
+  IconLayoutSidebar,
+  IconLayoutSidebarRight,
+  IconLayoutAlignCenter,
+} from "@tabler/icons-react";
+import type { WidthMode, ColumnsLayout } from "@docmost/editor-ext";
+import { useTranslation } from "react-i18next";
+import classes from "../common/toolbar-menu.module.css";
+
+type LayoutPreset = {
+  layout: ColumnsLayout;
+  label: string;
+  icon: React.ElementType;
+};
+
+const twoColumnPresets: LayoutPreset[] = [
+  { layout: "two_equal", label: "Equal columns", icon: IconColumns2 },
+  {
+    layout: "two_left_sidebar",
+    label: "Left sidebar",
+    icon: IconLayoutSidebar,
+  },
+  {
+    layout: "two_right_sidebar",
+    label: "Right sidebar",
+    icon: IconLayoutSidebarRight,
+  },
+];
+
+const threeColumnPresets: LayoutPreset[] = [
+  { layout: "three_equal", label: "Equal columns", icon: IconColumns3 },
+  {
+    layout: "three_with_sidebars",
+    label: "Wide center",
+    icon: IconLayoutAlignCenter,
+  },
+  {
+    layout: "three_left_wide",
+    label: "Left wide",
+    icon: IconLayoutSidebarRight,
+  },
+  { layout: "three_right_wide", label: "Right wide", icon: IconLayoutSidebar
+  },
+];
+
+function getPresetsForCount(count: number): LayoutPreset[] {
+  if (count === 2) return twoColumnPresets;
+  if (count === 3) return threeColumnPresets;
+  return [];
+}
+
+export function ColumnsMenu({ editor }: EditorMenuProps) {
+  const { t } = useTranslation();
+  const [isCountOpen, setIsCountOpen] = useState(false);
+
+  const shouldShow = useCallback(
+    ({ state }: ShouldShowProps) => {
+      if (!state) return false;
+      if (!editor.isActive("columns")) return false;
+
+      const parent = findParentNode(
+        (node: PMNode) => node.type.name === "columns",
+      )(state.selection);
+      if (!parent) return false;
+
+      const dom = editor.view.nodeDOM(parent.pos) as HTMLElement;
+      if (!dom) return false;
+
+      const rect = dom.getBoundingClientRect();
+      return rect.bottom > 0 && rect.top < window.innerHeight;
+    },
+    [editor],
+  );
+
+  const editorState = useEditorState({
+    editor,
+    selector: (ctx) => {
+      if (!ctx.editor) return null;
+
+      const { selection } = ctx.editor.state;
+      const parent = findParentNode(
+        (node: PMNode) => node.type.name === "columns",
+      )(selection);
+
+      return {
+        columnCount: parent?.node.childCount || 2,
+        layout: (parent?.node.attrs.layout as ColumnsLayout) || "two_equal",
+        isNormal: ctx.editor.isActive("columns", { widthMode: "normal" }),
+        isWide: ctx.editor.isActive("columns", { widthMode: "wide" }),
+      };
+    },
+  });
+
+  const getReferencedVirtualElement = useCallback(() => {
+    if (!editor) return;
+    const { selection } = editor.state;
+    const predicate = (node: PMNode) => node.type.name === "columns";
+    const parent = findParentNode(predicate)(selection);
+
+    if (parent) {
+      const dom = editor.view.nodeDOM(parent?.pos) as HTMLElement;
+      const domRect = dom.getBoundingClientRect();
+
+      // Columns entirely out of viewport — return real rect so menu goes off-screen
+      if (domRect.bottom <= 0 || domRect.top >= window.innerHeight) {
+        return {
+          getBoundingClientRect: () => domRect,
+          getClientRects: () => [domRect],
+        };
+      }
+
+      // Clamp bottom so menu stays within viewport when columns extend below it
+      // 55px = 15px offset + ~40px menu height
+      const maxBottom = window.innerHeight - 55;
+      if (domRect.bottom > maxBottom) {
+        const clamped = new DOMRect(
+          domRect.x,
+          domRect.y,
+          domRect.width,
+          maxBottom - domRect.y,
+        );
+        return {
+          getBoundingClientRect: () => clamped,
+          getClientRects: () => [clamped],
+        };
+      }
+
+      return {
+        getBoundingClientRect: () => domRect,
+        getClientRects: () => [domRect],
+      };
+    }
+
+    const domRect = posToDOMRect(editor.view, selection.from, selection.to);
+    return {
+      getBoundingClientRect: () => domRect,
+      getClientRects: () => [domRect],
+    };
+  }, [editor]);
+
+  const setColumnCount = useCallback(
+    (count: number) => {
+      editor
+        .chain()
+        .focus(undefined, { scrollIntoView: false })
+        .setColumnCount(count)
+        .run();
+      setIsCountOpen(false);
+    },
+    [editor],
+  );
+
+  const setLayout = useCallback(
+    (layout: ColumnsLayout) => {
+      editor
+        .chain()
+        .focus(undefined, { scrollIntoView: false })
+        .setColumnsLayout(layout)
+        .run();
+    },
+    [editor],
+  );
+
+  const columnCount = editorState?.columnCount || 2;
+  const currentLayout = editorState?.layout || "two_equal";
+  const presets = getPresetsForCount(columnCount);
+
+  return (
+    <BaseBubbleMenu
+      editor={editor}
+      pluginKey="columns-menu"
+      updateDelay={0}
+      getReferencedVirtualElement={getReferencedVirtualElement}
+      options={{
+        placement: "bottom",
+        offset: {
+          mainAxis: 5,
+        },
+        flip: false,
+      }}
+      shouldShow={shouldShow}
+    >
+      <div className={classes.toolbar}>
+        <Popover opened={isCountOpen} onChange={setIsCountOpen} withArrow>
+          <Popover.Target>
+            <Button
+              variant="subtle"
+              color="dark"
+              size="compact-sm"
+              rightSection={<IconChevronDown size={12} />}
+              onClick={() => setIsCountOpen(!isCountOpen)}
+              aria-label={t("Column count")}
+            >
+              {t("{{count}} Columns", { count: columnCount })}
+            </Button>
+          </Popover.Target>
+          <Popover.Dropdown p={4}>
+            <Button.Group orientation="vertical">
+              {[2, 3, 4, 5].map((n) => (
+                <Button
+                  key={n}
+                  variant={n === columnCount ? "light" : "subtle"}
+                  color={n === columnCount ? "blue" : "dark"}
+                  justify="space-between"
+                  fullWidth
+                  rightSection={
+                    n === columnCount ? <IconCheck size={14} /> : null
+                  }
+                  onClick={() => setColumnCount(n)}
+                  size="xs"
+                >
+                  {t("{{count}} Columns", { count: n })}
+                </Button>
+              ))}
+            </Button.Group>
+          </Popover.Dropdown>
+        </Popover>
+
+        {presets.length > 0 && <div className={classes.divider} />}
+
+        {presets.map((preset) => (
+          <Tooltip key={preset.layout} position="top" label={t(preset.label)}>
+            <ActionIcon
+              onClick={() => setLayout(preset.layout)}
+              size="lg"
+              aria-label={t(preset.label)}
+              variant="subtle"
+              className={clsx({
+                [classes.active]: currentLayout === preset.layout,
+              })}
+            >
+              <preset.icon size={18} />
+            </ActionIcon>
+          </Tooltip>
+        ))}
+      </div>
+    </BaseBubbleMenu>
+  );
+}
+
+export default ColumnsMenu;

apps/client/src/features/editor/components/slash-menu/menu-items.ts

@@ -20,6 +20,8 @@ import {
   IconCalendar,
   IconAppWindow,
   IconSitemap,
+  IconColumns3,
+  IconColumns2,
 } from "@tabler/icons-react";
 import {
   CommandProps,
@@ -31,6 +33,8 @@ import { uploadAttachmentAction } from "@/features/editor/components/attachment/
 import IconExcalidraw from "@/components/icons/icon-excalidraw";
 import IconMermaid from "@/components/icons/icon-mermaid";
 import IconDrawio from "@/components/icons/icon-drawio";
+import { IconColumns4 } from "@/components/icons/icon-columns-4";
+import { IconColumns5 } from "@/components/icons/icon-columns-5";
 import {
   AirtableIcon,
   FigmaIcon,
@@ -390,6 +394,58 @@ const CommandGroups: SlashMenuGroupedItemsType = {
         editor.chain().focus().deleteRange(range).insertSubpages().run();
       },
     },
+    {
+      title: "2 Columns",
+      description: "Split content into two columns.",
+      searchTerms: ["columns", "layout", "split", "side"],
+      icon: IconColumns2,
+      command: ({ editor, range }: CommandProps) =>
+        editor
+          .chain()
+          .focus()
+          .deleteRange(range)
+          .insertColumns({ layout: "two_equal" })
+          .run(),
+    },
+    {
+      title: "3 Columns",
+      description: "Split content into three columns.",
+      searchTerms: ["columns", "layout", "split", "triple"],
+      icon: IconColumns3,
+      command: ({ editor, range }: CommandProps) =>
+        editor
+          .chain()
+          .focus()
+          .deleteRange(range)
+          .insertColumns({ layout: "three_equal" })
+          .run(),
+    },
+    {
+      title: "4 Columns",
+      description: "Split content into four columns.",
+      searchTerms: ["columns", "layout", "split"],
+      icon: IconColumns4,
+      command: ({ editor, range }: CommandProps) =>
+        editor
+          .chain()
+          .focus()
+          .deleteRange(range)
+          .insertColumns({ layout: "four_equal" })
+          .run(),
+    },
+    {
+      title: "5 Columns",
+      description: "Split content into five columns.",
+      searchTerms: ["columns", "layout", "split"],
+      icon: IconColumns5,
+      command: ({ editor, range }: CommandProps) =>
+        editor
+          .chain()
+          .focus()
+          .deleteRange(range)
+          .insertColumns({ layout: "five_equal" })
+          .run(),
+    },
     {
       title: "Iframe embed",
       description: "Embed any Iframe",

apps/client/src/features/editor/extensions/extensions.ts

@@ -43,6 +43,8 @@ import {
   Highlight,
   UniqueID,
   SharedStorage,
+  Columns,
+  Column,
 } from "@docmost/editor-ext";
 import {
   randomElement,
@@ -124,7 +126,7 @@ export const mainExtensions = [
     filterTransaction: (transaction) => !isChangeOrigin(transaction),
   }),
   Placeholder.configure({
-    placeholder: ({ node }) => {
+    placeholder: ({ editor, node, pos }) => {
       if (node.type.name === "heading") {
         return i18n.t("Heading {{level}}", { level: node.attrs.level });
       }
@@ -132,6 +134,10 @@ export const mainExtensions = [
         return i18n.t("Toggle title");
       }
       if (node.type.name === "paragraph") {
+        const $pos = editor.state.doc.resolve(pos);
+        if ($pos.parent.type.name === "column") {
+          return i18n.t("Write...");
+        }
         return i18n.t('Write anything. Enter "/" for commands');
       }
     },
@@ -302,6 +308,8 @@ export const mainExtensions = [
       };
     },
   }).configure(),
+  Columns,
+  Column,
 ] as any;
 
 type CollabExtensions = (provider: HocuspocusProvider, user: IUser) => any[];

apps/client/src/features/editor/page-editor.tsx

@@ -67,6 +67,7 @@ import { jwtDecode } from "jwt-decode";
 import { searchSpotlight } from "@/features/search/constants.ts";
 import { useEditorScroll } from "./hooks/use-editor-scroll";
 import { EditorAiMenu } from "@/ee/ai/components/editor/ai-menu/ai-menu";
+import ColumnsMenu from "@/features/editor/components/columns/columns-menu.tsx";
 
 interface PageEditorProps {
   pageId: string;
@@ -416,6 +417,7 @@ export default function PageEditor({
             <SubpagesMenu editor={editor} />
             <ExcalidrawMenu editor={editor} />
             <DrawioMenu editor={editor} />
+            <ColumnsMenu editor={editor} />
             <LinkMenu editor={editor} appendTo={menuContainerRef} />
           </div>
         )}

apps/client/src/features/editor/styles/columns.css

@@ -0,0 +1,108 @@
+div[data-type="columns"] {
+  display: flex;
+  gap: 1rem;
+  margin: 0.75rem 0;
+  padding: 0.5em;
+}
+
+div[data-type="columns"] > div[data-type="column"] {
+  flex: 1;
+  min-width: 0;
+}
+
+div[data-type="columns"] > div[data-type="column"] + div[data-type="column"] {
+  border-left: 1px solid transparent;
+  padding-left: 1rem;
+  transition: border 0.3s;
+}
+
+div[data-type="columns"]:hover
+  > div[data-type="column"]
+  + div[data-type="column"] {
+  border-left: 1px solid
+    light-dark(var(--mantine-color-gray-3), var(--mantine-color-gray-7));
+}
+
+/* Confluence layout types */
+div[data-type="columns"][data-layout="two_left_sidebar"]
+  > div[data-type="column"]:first-child {
+  flex: 1;
+}
+
+div[data-type="columns"][data-layout="two_left_sidebar"]
+  > div[data-type="column"]:last-child {
+  flex: 2;
+}
+
+div[data-type="columns"][data-layout="two_right_sidebar"]
+  > div[data-type="column"]:first-child {
+  flex: 2;
+}
+
+div[data-type="columns"][data-layout="two_right_sidebar"]
+  > div[data-type="column"]:last-child {
+  flex: 1;
+}
+
+div[data-type="columns"][data-layout="three_left_wide"]
+  > div[data-type="column"]:first-child {
+  flex: 2;
+}
+
+div[data-type="columns"][data-layout="three_right_wide"]
+  > div[data-type="column"]:last-child {
+  flex: 2;
+}
+
+div[data-type="columns"][data-layout="three_with_sidebars"]
+  > div[data-type="column"]:first-child,
+div[data-type="columns"][data-layout="three_with_sidebars"]
+  > div[data-type="column"]:last-child {
+  flex: 1;
+}
+
+div[data-type="columns"][data-layout="three_with_sidebars"]
+  > div[data-type="column"]:nth-child(2) {
+  flex: 2;
+}
+
+/* Stack columns vertically on small viewports */
+@media (max-width: 820px) {
+  div[data-type="columns"] {
+    flex-direction: column;
+  }
+
+  div[data-type="columns"] > div[data-type="column"] + div[data-type="column"] {
+    border-left: none;
+    padding-left: 0;
+  }
+
+  div[data-type="columns"]:hover
+    > div[data-type="column"]
+    + div[data-type="column"] {
+    border-left: none;
+  }
+}
+
+/* Wide width mode — extends columns to full container width */
+div[data-type="columns"][data-width-mode="wide"] {
+  margin-left: -3rem;
+  margin-right: -3rem;
+  width: calc(100% + 6rem);
+}
+
+@media (max-width: $mantine-breakpoint-sm) {
+  div[data-type="columns"][data-width-mode="wide"] {
+    margin-left: -1rem;
+    margin-right: -1rem;
+    width: calc(100% + 2rem);
+  }
+}
+
+@media print {
+  div[data-type="columns"][data-width-mode="wide"] {
+    margin-left: 0;
+    margin-right: 0;
+    width: 100%;
+  }
+}

apps/client/src/features/editor/styles/index.css

@@ -13,3 +13,4 @@
 @import "./mention.css";
 @import "./ordered-list.css";
 @import "./highlight.css";
+@import "./columns.css";

apps/server/src/collaboration/collaboration.util.ts

@@ -35,6 +35,8 @@ import {
   UniqueID,
   addUniqueIdsToDoc,
   htmlToMarkdown,
+  Columns,
+  Column,
 } from '@docmost/editor-ext';
 import { generateText, getSchema, JSONContent } from '@tiptap/core';
 import { generateHTML, generateJSON } from '../common/helpers/prosemirror/html';
@@ -91,6 +93,8 @@ export const tiptapExtensions = [
   Embed,
   Mention,
   Subpages,
+  Columns,
+  Column,
 ] as any;
 
 export function jsonToHtml(tiptapJson: any) {

packages/editor-ext/src/index.ts

@@ -25,3 +25,4 @@ export * from "./lib/heading/heading";
 export * from "./lib/unique-id";
 export * from "./lib/shared-storage";
 export * from "./lib/recreate-transform";
+export * from "./lib/columns";

packages/editor-ext/src/lib/columns/column.ts

@@ -0,0 +1,127 @@
+import { Node, mergeAttributes, findParentNode } from "@tiptap/core";
+import { TextSelection } from "prosemirror-state";
+
+export interface ColumnOptions {
+  HTMLAttributes: Record<string, any>;
+}
+
+export interface ColumnAttributes {
+  width?: number | null;
+}
+
+declare module "@tiptap/core" {
+  interface Commands<ReturnType> {
+    column: {
+      setColumnWidth: (width: number | null) => ReturnType;
+    };
+  }
+}
+
+export const Column = Node.create<ColumnOptions>({
+  name: "column",
+  group: "block",
+  content: "block+",
+  defining: true,
+  isolating: true,
+  selectable: false,
+
+  addOptions() {
+    return {
+      HTMLAttributes: {},
+    };
+  },
+
+  addAttributes() {
+    return {
+      width: {
+        default: null,
+        parseHTML: (element) => {
+          const value = element.getAttribute("data-width");
+          return value ? parseFloat(value) : null;
+        },
+        renderHTML: (attributes: ColumnAttributes) => {
+          if (!attributes.width) return {};
+          return {
+            "data-width": attributes.width,
+            style: `flex: ${attributes.width}`,
+          };
+        },
+      },
+    };
+  },
+
+  parseHTML() {
+    return [
+      {
+        tag: `div[data-type="${this.name}"]`,
+      },
+    ];
+  },
+
+  renderHTML({ HTMLAttributes }) {
+    return [
+      "div",
+      mergeAttributes(
+        { "data-type": this.name },
+        this.options.HTMLAttributes,
+        HTMLAttributes,
+      ),
+      0,
+    ];
+  },
+
+  addKeyboardShortcuts() {
+    const jumpToColumn = (direction: 1 | -1) => () => {
+      const { state, dispatch } = this.editor.view;
+
+      const columns = findParentNode(
+        (node) => node.type.name === "columns",
+      )(state.selection);
+      if (!columns) return false;
+
+      const column = findParentNode(
+        (node) => node.type.name === "column",
+      )(state.selection);
+      if (!column) return false;
+
+      let currentIndex = -1;
+      columns.node.forEach((_child, offset, index) => {
+        if (columns.pos + 1 + offset === column.pos) {
+          currentIndex = index;
+        }
+      });
+
+      const targetIndex = currentIndex + direction;
+      if (targetIndex < 0 || targetIndex >= columns.node.childCount) {
+        return false;
+      }
+
+      let offset = 0;
+      for (let j = 0; j < targetIndex; j++) {
+        offset += columns.node.child(j).nodeSize;
+      }
+
+      const targetPos = columns.pos + 1 + offset + 1 + 1;
+      if (dispatch) {
+        dispatch(
+          state.tr.setSelection(TextSelection.create(state.doc, targetPos)),
+        );
+      }
+      return true;
+    };
+
+    return {
+      Tab: jumpToColumn(1),
+      "Shift-Tab": jumpToColumn(-1),
+    };
+  },
+
+  addCommands() {
+    return {
+      setColumnWidth:
+        (width) =>
+        ({ commands }) =>
+          commands.updateAttributes("column", { width }),
+    };
+  },
+});

packages/editor-ext/src/lib/columns/columns.ts

@@ -0,0 +1,178 @@
+import { Node, mergeAttributes, findParentNode } from "@tiptap/core";
+import { Fragment, Node as PMNode } from "prosemirror-model";
+
+export type ColumnsLayout =
+  | "two_equal"
+  | "two_left_sidebar"
+  | "two_right_sidebar"
+  | "three_equal"
+  | "three_left_wide"
+  | "three_right_wide"
+  | "three_with_sidebars"
+  | "four_equal"
+  | "five_equal";
+
+export interface ColumnsOptions {
+  HTMLAttributes: Record<string, any>;
+}
+
+export type WidthMode = "normal" | "wide";
+
+export interface ColumnsAttributes {
+  layout?: ColumnsLayout;
+  widthMode?: WidthMode;
+}
+
+declare module "@tiptap/core" {
+  interface Commands<ReturnType> {
+    columns: {
+      insertColumns: (attributes?: ColumnsAttributes) => ReturnType;
+      setColumnsWidthMode: (widthMode: WidthMode) => ReturnType;
+      setColumnCount: (count: number) => ReturnType;
+      setColumnsLayout: (layout: ColumnsLayout) => ReturnType;
+    };
+  }
+}
+
+function columnCountFromLayout(layout: string): number {
+  if (layout.startsWith("five")) return 5;
+  if (layout.startsWith("four")) return 4;
+  if (layout.startsWith("three")) return 3;
+  return 2;
+}
+
+function defaultLayoutForCount(count: number): ColumnsLayout {
+  if (count === 3) return "three_equal";
+  if (count === 4) return "four_equal";
+  if (count === 5) return "five_equal";
+  return "two_equal";
+}
+
+export const Columns = Node.create<ColumnsOptions>({
+  name: "columns",
+  group: "block",
+  content: "column+",
+  defining: true,
+  isolating: true,
+
+  addOptions() {
+    return {
+      HTMLAttributes: {},
+    };
+  },
+
+  addAttributes() {
+    return {
+      layout: {
+        default: "two_equal",
+        parseHTML: (element) => element.getAttribute("data-layout"),
+        renderHTML: (attributes: ColumnsAttributes) => ({
+          "data-layout": attributes.layout,
+        }),
+      },
+      widthMode: {
+        default: "normal",
+        parseHTML: (element) =>
+          element.getAttribute("data-width-mode") || "normal",
+        renderHTML: (attributes: ColumnsAttributes) => {
+          if (!attributes.widthMode || attributes.widthMode === "normal")
+            return {};
+          return { "data-width-mode": attributes.widthMode };
+        },
+      },
+    };
+  },
+
+  parseHTML() {
+    return [
+      {
+        tag: `div[data-type="${this.name}"]`,
+      },
+    ];
+  },
+
+  renderHTML({ HTMLAttributes }) {
+    return [
+      "div",
+      mergeAttributes(
+        { "data-type": this.name },
+        this.options.HTMLAttributes,
+        HTMLAttributes,
+      ),
+      0,
+    ];
+  },
+
+  addCommands() {
+    return {
+      insertColumns:
+        (attributes) =>
+        ({ commands }) => {
+          const layout = attributes?.layout || "two_equal";
+          const count = columnCountFromLayout(layout);
+          const columns = Array.from({ length: count }, () => ({
+            type: "column",
+            content: [{ type: "paragraph" }],
+          }));
+
+          return commands.insertContent({
+            type: this.name,
+            attrs: attributes,
+            content: columns,
+          });
+        },
+
+      setColumnsWidthMode:
+        (widthMode) =>
+        ({ commands }) =>
+          commands.updateAttributes("columns", { widthMode }),
+
+      setColumnCount:
+        (count: number) =>
+        ({ tr, state }) => {
+          const predicate = (node: PMNode) => node.type.name === "columns";
+          const parent = findParentNode(predicate)(state.selection);
+          if (!parent) return false;
+
+          const { node: columnsNode, pos: parentPos } = parent;
+          const currentCount = columnsNode.childCount;
+          if (count === currentCount || count < 2 || count > 5) return false;
+
+          const columnType = state.schema.nodes.column;
+          const paraType = state.schema.nodes.paragraph;
+          const newChildren: PMNode[] = [];
+
+          if (count > currentCount) {
+            for (let i = 0; i < currentCount; i++) {
+              newChildren.push(columnsNode.child(i));
+            }
+            for (let i = currentCount; i < count; i++) {
+              newChildren.push(columnType.create(null, paraType.create()));
+            }
+          } else {
+            for (let i = 0; i < count - 1; i++) {
+              newChildren.push(columnsNode.child(i));
+            }
+            let mergedContent = columnsNode.child(count - 1).content;
+            for (let j = count; j < currentCount; j++) {
+              mergedContent = mergedContent.append(columnsNode.child(j).content);
+            }
+            newChildren.push(columnType.create(null, mergedContent));
+          }
+
+          const newLayout = defaultLayoutForCount(count);
+          const newNode = columnsNode.type.create(
+            { ...columnsNode.attrs, layout: newLayout },
+            Fragment.from(newChildren),
+          );
+          tr.replaceWith(parentPos, parentPos + columnsNode.nodeSize, newNode);
+          return true;
+        },
+
+      setColumnsLayout:
+        (layout) =>
+        ({ commands }) =>
+          commands.updateAttributes("columns", { layout }),
+    };
+  },
+});

packages/editor-ext/src/lib/columns/index.ts

@@ -0,0 +1,4 @@
+export { Columns } from "./columns";
+export type { ColumnsOptions, ColumnsAttributes, ColumnsLayout, WidthMode } from "./columns";
+export { Column } from "./column";
+export type { ColumnOptions, ColumnAttributes } from "./column";