pull down to refresh

The errors I get on browserstack.com imply the browsers don't support modern javascript or something. I'm not sure why that would change other than us turning on production source maps in the latest deployment.
VM60:36TypeError: Right side of assignment cannot be destructured(anonymous function) @ VM60:36global code @ VM60:38 _app-b751a051034d52aa.js:1 SyntaxError: Cannot declare a let variable twice: 'e'.(anonymous function) @ _app-b751a051034d52aa.js:1 6849-35bdba25632b2baa.js:1 SyntaxError: Unexpected token '...'. Expected a property name.(anonymous function) @ 6849-35bdba25632b2baa.js:1 575-a4dbeee94cc2064e.js:1 SyntaxError: Invalid regular expression: unrecognized character after (?