title: ApplePaySession is not defined no-undef error in React
body: <p>I am just trying to validate whether apple pay is supported on browser or not  with following code. But it gives error on safari (ipad) / macbook.</p>
  <pre><code>ApplePaySession' is not defined no-undef
  </code></pre>
  <p>Following code, I had written in ReactJs.</p>
  <pre><code>if (window.ApplePaySession) {
        if (ApplePaySession.canMakePayments) {
          alert('hi, I can do ApplePay.....')
        }
  </code></pre>
  <p>but gives undefined error!</p>
  <p>If anyone can help? Why ApplePaySession is undefined? Do we need to import ApplePaySession? Or do we need to add any sdk?</p>