Code

editor.tsx

import { createEditor } from 'prosekit/core'
import 'prosekit/basic/style.css'
import { ProseKit } from 'prosekit/react'
import { useMemo } from 'react'

import { defineExtension } from './extension'

export default function Editor() {
  const editor = useMemo(() => {
    return createEditor({ extension: defineExtension(), defaultContent })
  }, [])

  return (
    <ProseKit editor={editor}>
      <div className='box-border h-full w-full min-h-36 overflow-y-hidden overflow-x-hidden rounded-md border border-solid border-gray-200 shadow dark:border-zinc-700 flex flex-col bg-white dark:bg-neutral-900'>
        <div className='relative w-full flex-1 box-border overflow-y-scroll'>
          <div ref={editor.mount} className='ProseMirror box-border min-h-full px-[max(4rem,_calc(50%-20rem))] py-8 outline-none outline-0 [&_span[data-mention="user"]]:text-blue-500 [&_span[data-mention="tag"]]:text-violet-500 [&_pre]:text-white [&_pre]:bg-zinc-800'></div>
        </div>
      </div>
    </ProseKit>
  )
}

const defaultContent = `
<p>Click the gap between two images or press arrow keys to see the gap cursor between two images</p>
<img src="https://placehold.co/200x100" />
<img src="https://placehold.co/200x100" />
`

extension.ts

import {
  defineBaseKeymap,
  defineDoc,
  defineParagraph,
  defineText,
  union,
} from 'prosekit/core'
import { defineGapCursor } from 'prosekit/extensions/gap-cursor'
import { defineImage } from 'prosekit/extensions/image'

export function defineExtension() {
  return union(
    defineBaseKeymap(),
    defineDoc(),
    defineText(),
    defineParagraph(),
    defineGapCursor(),
    defineImage(),
  )
}

export type EditorExtension = ReturnType<typeof defineExtension>