TypeError: Class extends value undefined is not a function or null

[robinelvin]

I get the following error when trying to use this module in my tests:

TypeError: Class extends value undefined is not a function or null
  
  at Object.relayMock (node_modules/relay-testing-utils/build/relay-mock.js:9:31)
  at Object.<anonymous> (src/components/__mocks__/react-relay.js:6:49)
  at Object.<anonymous> (src/components/filter.tsx:10:2)
  at Object.<anonymous> (src/components/__tests__/filter.test.tsx:2:1)

[robinelvin]

Ah, I've just realised that I'm using Relay Modern....

[meuschke]

@robinelvin Yes its not compatible with modern. Your more then welcome to change it and make a PR. In the moment I don´t have the time to fix it.