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Generics in TypeScript Quiz
This quiz explores Generics in TypeScript, including topics such as generic functions, generic classes, constraints in generics, and built-in generic types. It aims to provide a comprehensive understanding of how generics enhance code reusability, flexibility, and type safety in TypeScript.
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Question 1
What is the primary purpose of generics in TypeScript?
To create dynamic functions without type checking.
To enforce strict types on all variables.
To allow type flexibility while maintaining type safety.
To remove the need for interfaces and type aliases.
Question 2
Which of the following is a correct example of a generic function?
function identity<T>(value: T): T {
return value;
}
The function uses a generic type <T> for flexibility.
<T> is unnecessary and makes the function invalid.
The identity function is not generic.
The identity function must define a fixed type for T.
Question 3
What is the output type of the following generic function?
function wrap<T>(value: T): { value: T } {
return { value };
}
T
{ value: T }
void
unknown
Question 4
Which of the following defines a generic class?
class Box<T> {
private content: T;
constructor(content: T) {
this.content = content;
}
getContent(): T {
return this.content;
}
}
Box is a generic class where T can be replaced with a specific type.
T must always be a string in this class.
T is a built-in generic type.
The class is invalid because it uses <T>.
Question 5
What is the purpose of constraints in generics?
To limit the use of generics to specific classes only.
To enforce that a type parameter meets certain requirements
To ensure that generics cannot be used in functions.
To restrict the number of type parameters in a function.
Question 6
Which of the following constrains a generic type to objects with a length property?
function logLength<T extends { length: number }>(arg: T): void {
console.log(arg.length);
}
The generic type T must be a number.
The generic type T must be a string.
The generic type T must have a length property.
The function is invalid because T cannot have constraints.
Question 7
What is the purpose of the Partial<T> built-in generic type in TypeScript?
To make all properties of T required.
To enforce strict null checking on T.
To make all properties of T optional.
To exclude properties from T.
Question 8
How is the Record
generic type used in TypeScript?
To define an object type with keys of type K and values of type V.
To merge two types K and V.
To restrict the properties of K to a single type.
To make K optional in all cases.
Question 9
What is the key difference between generics and type aliases?
Generics enforce strict types, while type aliases do not.
Type aliases are more flexible than generics.
Generics allow type flexibility, whereas type aliases define specific structures.
Generics are only used for arrays, while type aliases are used for objects.
Question 10
Which of the following is a correct use of the ReadonlyArray<T> built-in generic type?
function printNumbers(numbers: ReadonlyArray<number>): void {
numbers.forEach((num) => console.log(num));
// numbers.push(10); // Error
}
It ensures the array numbers cannot be modified.
It allows adding new elements to numbers.
It is identical to a regular array.
It throws an error at runtime if numbers is modified.
There are 10 questions to complete.
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