@domternal/extension-image

An image node for the Domternal editor: corner-handle resizing, float/text-wrapping controls (none, left, center, right), paste and drag-and-drop file upload through your own uploadHandler, a markdown ![alt](src "title") input rule, and defense-in-depth XSS validation on src (blocks javascript:, vbscript:, file:, and non-image data: URLs across parse, render, command, and input-rule layers). Block-level by default, optional inline mode.

Links

Website    •    Documentation    •    Live examples

Install

pnpm add @domternal/extension-image

@domternal/core and @domternal/pm are peer dependencies (you already have them if you are building a Domternal editor).

Usage

import { Editor, Document, Paragraph, Text } from '@domternal/core';
import { Image } from '@domternal/extension-image';

const editor = new Editor({
  extensions: [
    Document,
    Paragraph,
    Text,
    Image.configure({
      // Optional: enables paste/drop upload. Return the stored URL.
      uploadHandler: async (file) => {
        const form = new FormData();
        form.append('file', file);
        const res = await fetch('/api/upload', { method: 'POST', body: form });
        const { url } = (await res.json()) as { url: string };
        return url;
      },
    }),
  ],
});

// Insert an image
editor.commands.setImage({ src: 'https://example.com/photo.jpg', alt: 'A photo' });

// Wrap text around the selected image
editor.commands.setImageFloat('left');

// Remove the selected image
editor.commands.deleteImage();

Options

Image.configure({ ... }) accepts:

• inline (boolean, default false) - render images inline within paragraphs instead of as block nodes.
• allowBase64 (boolean, default true) - permit data:image/ URLs; when false, only non-data sources are allowed.
• uploadHandler ((file: File) => Promise<string> or null, default null) - when set, enables image upload on paste and drop.
• allowedMimeTypes (string[]) - MIME types accepted for upload (defaults to image/jpeg, image/png, image/gif, image/webp, image/svg+xml, image/avif).
• maxFileSize (number, default 0) - max upload size in bytes; 0 means unlimited.
• onUploadStart / onUploadError - callbacks fired when an upload begins or fails.
• HTMLAttributes (Record<string, unknown>) - attributes merged onto the rendered <img>.

Commands

• setImage(attributes: SetImageOptions) - insert an image (src required; optional alt, title, width, height, loading, crossorigin, float).
• setImageFloat(float: ImageFloat) - set wrapping on the selected image ('none' | 'left' | 'right' | 'center').
• deleteImage() - delete the selected image.

Editing UI

The user-facing counterpart to the commands above:

• Selecting an image opens a bubble menu with wrapping controls (Inline / Left / Center / Right), an "Edit alt text" action, and Delete.
• The main toolbar and the slash (floating) menu both expose an "Image" action that opens a popover with a URL field and an alt-text field, plus a button to browse for a local file.
• When uploadHandler is set, pasting or dropping an image file uploads it through the handler and inserts the returned URL. Without an uploadHandler, pasted and dropped images are inlined as base64 data: URLs.