ReactNative - "expo start" works with tsx file which is not conforming typescript grammar

I've just started reactive native.I created a project with "expo init" with "blank (TypeScript)" option selected.

Created a component called GoalItem.tsx as below,

import React from 'react'import { View, Text, StyleSheet } from 'react-native'const GoalItem = props => (<View><Text>{props.title}</Text></View>)export default GoalItem

It's just a javascript code in tsx file.When typed tsc in the terminal, I get errors related to typescript grammar which is expected.

When I typed expo start, it just works well without any warnings nor errors.

Questions:How do we make expo start to check typescript grammar first?

This is my tsconfig.json file

{"extends": "expo/tsconfig.base","compilerOptions": {"strict": true  }}