React

HTML

<div id="app"></div>

React

class TodoApp extends React.Component {
  constructor(props) {
    super(props)    
  }
  
  handleGoogleClick(){
  let url = 'https://docs.google.com/viewer?url=https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf';
  	window.open(url);
  }
  
   handleMicrosoftClick(){
  let url = 'https://view.officeapps.live.com/op/view.aspx?src=https://www2.le.ac.uk/webcentre/training-archive/121s/mm475s-sandbox/images/Test.docx';
  	window.open(url);
  }
  
  render() {  
    return (
    <div>
      <button onClick={() => this.handleGoogleClick()}>
       Google Viewer
      </button>
      
       <button onClick={() => this.handleMicrosoftClick()}>
       Microsoft Viewer
      </button>
      </div>
    );
  }
}

ReactDOM.render(<TodoApp />, document.querySelector("#app"))