Parameters type in Typescript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a function parameter with type number.

Typescript

function add(a: [1]) { return a + 10; }

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

Astring

Bnumber

Cboolean

Dany

Attempts:

3 left

💡 Hint

Common Mistakes

Using string type causes a type error when adding a number.

Using boolean is incorrect for numeric operations.

The parameter a must be of type number to add 10 correctly.

2fill in blank

medium

Complete the code to declare a function parameter with type string.

Typescript

function greet(name: [1]) { return `Hello, ${name}!`; }

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

Astring

Bobject

Cboolean

Dnumber

Attempts:

3 left

💡 Hint

Common Mistakes

Using number or boolean causes errors when concatenating strings.

The parameter name should be a string to use in the greeting message.

3fill in blank

hard

Fix the error in the function parameter type to accept an array of numbers.

Typescript

function sum(numbers: [1]) { return numbers.reduce((a, b) => a + b, 0); }

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

Anumber

Bstring[]

Cnumber[]

Dany

Attempts:

3 left

💡 Hint

Common Mistakes

Using number instead of number[] causes errors because a single number is expected, not an array.

The parameter numbers must be an array of numbers, written as number[].

4fill in blank

hard

Fill both blanks to declare a function with two parameters: a string and a boolean.

Typescript

function checkStatus(name: [1], isActive: [2]) { return `${name} is ${isActive ? 'active' : 'inactive'}`; }

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

Astring

Bboolean

Cnumber

Dany

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the types or using number instead of boolean.

The first parameter name is a string, and the second isActive is a boolean.

5fill in blank

hard

Fill all three blanks to declare a function with parameters: a string, a number, and an optional boolean.

Typescript

function createUser(name: [1], age: [2], isAdmin?: [3]) { return { name, age, isAdmin }; }

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

Astring

Bnumber

Cboolean

Dany

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the optional parameter syntax or using wrong types.

The parameters are name as string, age as number, and optional isAdmin as boolean.