Apple Pay on the Web Emporium Web App SyntaxError

I'm having trouble running the Emporium Web app - here's what I've tried:

• Went to: https://developer.apple.com/library/content/samplecode/EmporiumWeb/Introduction/Intro.html
• Downloaded the sample code
• Extracted it
• Copied my .pem certificates into the /certificates folder
• npm install
• npm start
• I get this error:

SyntaxError: Unexpected reserved word

Please note this is a different issue that cannot be resolved by following the answers in unexpected reserved word import in node.js.

How can I run this Emporium web app?

via Ryan