File Handler

FileHandlerPlugin detects files in paste and drop events. It does not upload, preview, or insert them: those are application decisions.

const fileHandler = FileHandlerPlugin.configure({
  allowedMimeTypes: ['image/*', 'application/pdf'],
  onPaste: ({ files, position, html, text }) => this.uploadFiles(files, { position, html, text }),
  onDrop: ({ files, position }) => this.uploadFiles(files, { position }),
});

Return true when your callback consumes the event. Return false/void to let other ProseMirror handlers continue. MIME filters accept exact values and wildcards such as image/*. The callback receives Qalma-owned values only: files, an optional document position, and clipboard HTML/plain text—no EditorView leaks into your Angular layer.

File.type and filenames are supplied by the client. MIME filtering is a UX filter, not security validation. Enforce file size, inspect magic bytes, decode images with resource limits, scan content, authorize storage, and generate safe filenames on the server. The callback's html value is raw clipboard metadata; never inject it into the DOM.

For image uploads, create a local preview if needed, send the file to your own backend, then call editor.execute('insertImage', value).