Multiple generic parameters in Typescript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a generic function with two type parameters.

Typescript

function pair<[1], U>(first: [1], second: U): [[1], U] {
  return [first, second];
}

Drag options to blanks, or click blank then click option'

AU

BT

CV

DS

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same letter for both generic parameters.

Using lowercase letters for generic parameters.

The first generic type parameter is usually named T. Here, T and U are used as generic parameters.

2fill in blank

medium

Complete the code to create a generic interface with two type parameters.

Typescript

interface Result<[1], U> {
  success: boolean;
  data: [1] | U;
}

Drag options to blanks, or click blank then click option'

AT

BR

CS

DU

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same name for both generic parameters.

Using lowercase letters.

The first generic parameter is named T, which is commonly used for generic types.

3fill in blank

hard

Fix the error in the generic function declaration with two parameters.

Typescript

function merge<[1], U>(obj1: [1], obj2: U): [1] & U {
  return { ...obj1, ...obj2 };
}

Drag options to blanks, or click blank then click option'

AU

Bt

CT

DV

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase letters for generic parameters.

Using the same letter for both parameters.

Generic type parameters must be uppercase letters. 'T' is correct, 't' is invalid.

4fill in blank

hard

Fill both blanks to declare a generic class with two type parameters and a method using them.

Typescript

class Pair<[1], [2]> {
  constructor(public first: [1], public second: [2]) {}
  getPair(): [[1], [2]] {
    return [this.first, this.second];
  }
}

Drag options to blanks, or click blank then click option'

AT

BU

CV

DS

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same letter for both generic parameters.

Using lowercase letters.

The generic class uses T and U as type parameters for the two types.

5fill in blank

hard

Fill all three blanks to create a generic function that takes two parameters and returns an object with keys and values of those types.

Typescript

function createMap<[1], [2]>(key: [1], value: [2]): { [1]: [2] } {
  return { [key]: value };
}

Drag options to blanks, or click blank then click option'

AK

BV

Ckey

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase letters for generic parameters.

Using the same name for generic parameters and function parameters.

The generic parameters are K and V for key and value types, and the key parameter is named 'key'.