Chapter quiz · Advanced Types

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8 questions on Advanced Types. Pass 70% to clear the chapter.

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Quiz

TS Advanced Types — Chapter Quiz

Eight questions on keyof, mapped, conditional, and utility types.

0/ 9

Question 1
1
Given type T = { a: string; b: number }, what is keyof T?
Astring | numberB"a" | "b"CT[]D{ a, b }
keyof T is the union of T's property name literals.
Question 2
2
What is the type of Result?
```
type T = { a: string; b: number };
type Result = T["b"];
```
AstringBnumberC"b"Dany
Indexed access T["b"] extracts the property's type — here, number.
Question 3
3
Which utility type makes every field optional?
AOptional<T>BPartial<T>CMaybe<T>DRequired<T>
Partial<T> makes every property of T optional. Required<T> is the opposite.
Question 4
4
Which utility selects a subset of keys?
APick<T, K>BOmit<T, K>CSubset<T, K>DKeys<T, K>
Pick<T, K> keeps only the listed keys. Omit<T, K> is the opposite — drop the listed keys.
Question 5
5
A conditional type T extends U ? X : Y distributes over unions when T is a naked type parameter.
TTrueFFalse
Distribution happens for *naked* generic params. Wrap in [T] extends [U] to disable it.
Question 6
6
The keyword that extracts a type from a position inside a conditional is ___.
infer X introduces a type variable bound to whatever matched the pattern. Used heavily in utilities like ReturnType and Awaited.
Question 7
7
What does this template literal type produce?
A"Hello, Ada!" | "Hello, Linus!"B"Hello, ${name}!"CstringD"Hello, Ada Linus!"
Template literal types distribute over union slots, producing every combination as a literal type.
Question 8
8
Which utility types extract pieces of a function signature?
Select all that apply.
AParameters<F>BReturnType<F>CAwaited<T>DPick<T, K>
Parameters<F> gives the tuple of param types; ReturnType<F> gives the return type. Awaited<T> unwraps Promises.