Why advanced types are needed in Typescript - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable with a string type.

Typescript

let name: [1] = "Alice";

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

Astring

Bnumber

Cany

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using number or boolean instead of string.

The string type tells TypeScript that the variable name should hold text.

2fill in blank

medium

Complete the code to define a function that returns a number.

Typescript

function getAge(): [1] {
  return 30;
}

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

Avoid

Bstring

Cnumber

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using string or void as return type.

The function returns a number, so the return type should be number.

3fill in blank

hard

Fix the error in the code by completing the type for the parameter.

Typescript

function greet(person: [1]) {
  console.log("Hello, " + person);
}

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

Aany

Bboolean

Cnumber

Dstring

Attempts:

3 left

💡 Hint

Common Mistakes

Using number or boolean causes errors.

The parameter person is used as text, so it should be a string.

4fill in blank

hard

Fill both blanks to create a type that can be either a string or a number.

Typescript

let value: [1] = 42;
value = [2];

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

Astring | number

B"hello"

Ctrue

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Using only string or number alone.

The type string | number means value can be a string or a number. Assigning "hello" is valid.

5fill in blank

hard

Fill all three blanks to create a function type that takes a number and returns a boolean.

Typescript

type Check = ([1]: [2]) => [3];

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

Anum

Bnumber

Cboolean

Dstring

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong parameter or return types.

The function type Check takes a parameter named num of type number and returns a boolean.