fix(web-pkg): embed pasted images in rich text editors

packages/web-pkg/src/editor/extensions/imageFileHandler.ts

@@ -1,17 +1,29 @@
 import FileHandler from '@tiptap/extension-file-handler'
 import type { Editor, Extension } from '@tiptap/core'
 
-const isSupportedImageFile = (file: File) => file.type.startsWith('image/')
+// Explicit list instead of `image/*`, because the file handler matches mime types exactly
+const supportedImageMimeTypes = [
+  'image/apng',
+  'image/avif',
+  'image/bmp',
+  'image/gif',
+  'image/jpeg',
+  'image/png',
+  'image/svg+xml',
+  'image/webp'
+]
+
+const isSupportedImageFile = (file: File) => supportedImageMimeTypes.includes(file.type)
 
 const readFileAsDataUrl = (file: File): Promise<string> =>
   new Promise((resolve, reject) => {
     const reader = new FileReader()
     reader.addEventListener('load', () => resolve(reader.result as string))
-    reader.addEventListener('error', () => reject(new Error('Failed to read dropped image file')))
+    reader.addEventListener('error', () => reject(new Error('Failed to read image file')))
     reader.readAsDataURL(file)
   })
 
-const insertDroppedImages = async (editor: Editor, files: File[], pos: number) => {
+const insertImages = async (editor: Editor, files: File[], pos: number) => {
   const imageFiles = files.filter(isSupportedImageFile)
   if (imageFiles.length === 0) {
     return
@@ -32,12 +44,19 @@ const insertDroppedImages = async (editor: Editor, files: File[], pos: number) =
       }
       insertPos += 1
     } catch {
-      // Ignore failed files and continue with remaining drops.
+      // Ignore failed files and continue with the remaining ones.
     }
   }
 }
 
 export const imageFileHandlerExtension = (): Extension =>
   FileHandler.configure({
-    onDrop: (editor, files, pos) => insertDroppedImages(editor, files, pos)
+    onDrop: (editor, files, pos) => insertImages(editor, files, pos),
+    // Copied images usually come with a text/html payload like `<img src="blob:...">`
+    // (e.g. from the preview app). Its source only lives as long as the page that created
+    // it, so consume the event and embed the image file itself instead.
+    onPaste: (editor, files) => insertImages(editor, files, editor.state.selection.from),
+    consumePasteEvent: true,
+    // Lets clipboard payloads without images (e.g. other copied files) reach the default paste
+    allowedMimeTypes: supportedImageMimeTypes
   })

packages/web-pkg/tests/unit/editor/extensions/imageFileHandler.spec.ts

@@ -0,0 +1,90 @@
+import { Editor } from '@tiptap/core'
+import Image from '@tiptap/extension-image'
+import StarterKit from '@tiptap/starter-kit'
+import { describe, expect, it, vi } from 'vitest'
+import { imageFileHandlerExtension } from '../../../../src/editor/extensions/imageFileHandler'
+
+function createEditor(): Editor {
+  return new Editor({
+    extensions: [
+      StarterKit,
+      Image.configure({ inline: false, allowBase64: true }),
+      imageFileHandlerExtension()
+    ]
+  })
+}
+
+function createClipboardEvent({ files = [], html = '' }: { files?: File[]; html?: string }) {
+  const event = new Event('paste', { bubbles: true, cancelable: true }) as ClipboardEvent
+
+  Object.defineProperty(event, 'clipboardData', {
+    value: {
+      files,
+      getData: (type: string) => (type === 'text/html' ? html : '')
+    }
+  })
+
+  return event
+}
+
+function getImageSources(editor: Editor) {
+  const sources: string[] = []
+  editor.state.doc.descendants((node) => {
+    if (node.type.name === 'image') {
+      sources.push(node.attrs.src)
+    }
+  })
+  return sources
+}
+
+describe('image file handler extension', () => {
+  it('embeds a pasted image file as data url instead of the html image source', async () => {
+    const editor = createEditor()
+    const file = new File(['image'], 'image.png', { type: 'image/png' })
+    const event = createClipboardEvent({
+      files: [file],
+      html: '<img src="blob:https://localhost/2c3c4f5e">'
+    })
+
+    try {
+      editor.view.dom.dispatchEvent(event)
+
+      expect(event.defaultPrevented).toBe(true)
+      await vi.waitFor(() => expect(getImageSources(editor)).toHaveLength(1))
+      expect(getImageSources(editor)[0]).toMatch(/^data:image\/png;base64,/)
+    } finally {
+      editor.destroy()
+    }
+  })
+
+  it('leaves clipboard payloads without image files to the default paste handling', () => {
+    const editor = createEditor()
+    const file = new File(['pdf'], 'document.pdf', { type: 'application/pdf' })
+    const event = createClipboardEvent({ files: [file], html: '<p>document.pdf</p>' })
+
+    try {
+      editor.view.dom.dispatchEvent(event)
+
+      expect(getImageSources(editor)).toHaveLength(0)
+      expect(editor.state.doc.textContent).toBe('document.pdf')
+    } finally {
+      editor.destroy()
+    }
+  })
+
+  it('does not paste images into read-only editors', async () => {
+    const editor = createEditor()
+    editor.setEditable(false)
+    const file = new File(['image'], 'image.png', { type: 'image/png' })
+    const event = createClipboardEvent({ files: [file] })
+
+    try {
+      editor.view.dom.dispatchEvent(event)
+
+      await new Promise((resolve) => setTimeout(resolve))
+      expect(getImageSources(editor)).toHaveLength(0)
+    } finally {
+      editor.destroy()
+    }
+  })
+})