seahub/frontend/src/shared-file-view-unknown.js

import React from 'react';
import ReactDom from 'react-dom';
import SharedFileView from './components/shared-file-view/shared-file-view';
import SharedFileViewTip from './components/shared-file-view/shared-file-view-tip';

const { err } = window.shared.pageOptions;

class SharedFileViewImage extends React.Component {
  render() {
    return <SharedFileView content={<FileContent />} />;
  }
}

class FileContent extends React.Component {
  render() {
    if (err) {
      return <SharedFileViewTip />;
    }
  }
}

ReactDom.render(<SharedFileViewImage />, document.getElementById('wrapper'));