Add `"strictNullChecks": true` to `tsconfig.json`. Will produce many errors. _Unrelated note:_ Add also `"alwaysStrict": true`. https://www.typescriptlang.org/docs/handbook/compiler-options.html
Add
"strictNullChecks": truetotsconfig.json. Will produce many errors.Unrelated note: Add also
"alwaysStrict": true.https://www.typescriptlang.org/docs/handbook/compiler-options.html