Quiz · 3 questions

🛡️ Strict Mode — The Flags That Make TS Honest

strict, noImplicitAny, strictNullChecks, noUncheckedIndexedAccess, exactOptionalPropertyTypes

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01What does noImplicitAny catch?

Hint

Try writing a function with one unannotated parameter and turn the flag on/off. The diff is one error message.

02What does noUncheckedIndexedAccess add?

Hint

Try arr[100] on a length-3 array with and without the flag. The type difference is the whole story.

03What does exactOptionalPropertyTypes change about optional fields?

Hint

The flag's name is exact: 'optional means missing, not explicitly undefined.' If your runtime code distinguishes the two, the types now do too.

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