The any type and why to avoid it in Typescript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable with the 'any' type.

Typescript

let data: [1];

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

Aany

Bstring

Cnumber

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'string' or 'number' instead of 'any' when you want no type checking.

The 'any' type allows a variable to hold any kind of value without type checking.

2fill in blank

medium

Complete the code to assign a string value to a variable typed as 'any'.

Typescript

let value: any = [1];

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

Atrue

B'hello'

C42

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around string values.

Assigning a string value requires quotes around the text.

3fill in blank

hard

Fix the error in the code by choosing the correct type instead of 'any'.

Typescript

function greet(name: [1]) {
  return 'Hello, ' + name;
}

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

Astring

Bboolean

Cnumber

Dany

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'any' loses type safety and can cause bugs.

The function expects a string for the name parameter, not 'any'.

4fill in blank

hard

Fill both blanks to create a typed object instead of using 'any'.

Typescript

let user: [1] = {
  name: 'Alice',
  age: [2]
};

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

A{ name: string; age: number }

Bany

C30

D'30'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'any' loses type safety.

Assigning age as a string instead of a number.

Use an object type with 'name' as string and 'age' as number, and assign a number value to age.

5fill in blank

hard

Fill all three blanks to avoid 'any' and use proper types in this function.

Typescript

function multiply(a: [1], b: [2]): [3] {
  return a * b;
}

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

Anumber

Bstring

Dany

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'any' loses type safety.

Using 'string' for parameters causes errors.

Both parameters and the return value should be numbers to multiply correctly and avoid 'any'.