Parameter type annotations in Typescript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a type annotation for the parameter name.

Typescript

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

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

Astring

Bany

Cboolean

Dnumber

Attempts:

3 left

💡 Hint

Common Mistakes

Using number or boolean instead of string.

Omitting the type annotation.

The parameter name should be a string because it represents a person's name.

2fill in blank

medium

Complete the code to add a type annotation for the parameter age.

Typescript

function setAge(age: [1]) {
  console.log(`Age set to ${age}`);
}

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

Aboolean

Bnumber

Cstring

Dobject

Attempts:

3 left

💡 Hint

Common Mistakes

Using string instead of number.

Using boolean or object incorrectly.

The parameter age should be a number because it represents a numeric value.

3fill in blank

hard

Fix the error by adding the correct type annotation for the parameter isActive.

Typescript

function setActive(isActive: [1]) {
  if (isActive) {
    console.log('Active');
  } else {
    console.log('Inactive');
  }
}

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 boolean.

Omitting the type annotation.

The parameter isActive should be a boolean because it represents a true/false value.

4fill in blank

hard

Fill both blanks to add type annotations for parameters title and pages.

Typescript

function createBook(title: [1], pages: [2]) {
  return `${title} has ${pages} pages.`;
}

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

Astring

Bboolean

Cnumber

Dobject

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the types between title and pages.

Using boolean or object incorrectly.

The title is a string because it is text, and pages is a number because it counts pages.

5fill in blank

hard

Fill all three blanks to add type annotations for parameters firstName, lastName, and age.

Typescript

function personInfo(firstName: [1], lastName: [2], age: [3]) {
  return `${firstName} ${lastName} is ${age} years old.`;
}

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

Anumber

Bstring

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the types for names and age.

Using boolean for any parameter.

Both firstName and lastName are string types because they are text, and age is a number.