How to reproduce:

• npm i
• npx tsc --noEmit should give you an error as expected
• npm i -D webpack-dev-server
• now if you run npx tsc --noEmit the error is gone

Same happens for the package @types/enzyme:

• undo the changes in package.json
• npm i -D @types/enzyme
• npx tsc --noEmit has no errors either