Momento/memento-note/lib/editor/markdown-paste-extension.ts

/**
 * markdown-paste-extension.ts
 *
 * TipTap extension that intercepts paste events. If the pasted plain text
 * looks like Markdown, it converts it to HTML and inserts it into the editor
 * as structured TipTap nodes — instead of inserting it as raw text.
 */

import { Extension } from '@tiptap/core'
import { Plugin, PluginKey } from '@tiptap/pm/state'
import { looksLikeMarkdown, markdownToHTML } from './markdown-export'

const MARKDOWN_PASTE_KEY = new PluginKey('markdownPaste')

export const MarkdownPasteExtension = Extension.create({
  name: 'markdownPaste',

  addProseMirrorPlugins() {
    const editor = this.editor

    return [
      new Plugin({
        key: MARKDOWN_PASTE_KEY,
        props: {
          handlePaste(_view, event) {
            const text = event.clipboardData?.getData('text/plain')
            if (!text || !looksLikeMarkdown(text)) return false

            event.preventDefault()

            try {
              const html = markdownToHTML(text)
              // Schedule after current event loop to avoid transaction conflicts
              setTimeout(() => {
                editor.commands.insertContent(html, {
                  parseOptions: { preserveWhitespace: 'full' },
                })
              }, 0)
            } catch {
              // Fallback: let TipTap handle the paste normally
              return false
            }

            return true
          },
        },
      }),
    ]
  },
})