Type alias vs inline types in Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a type alias for a user object.

Typescript

type User = [1];

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A[string, number]

B{ name: string; age: number }

Cstring | number

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using array syntax instead of object syntax.

Using union types instead of object types.

The correct syntax for a type alias defining an object type uses curly braces with property names and types.

2fill in blank

medium

Complete the function parameter type using an inline type instead of a type alias.

Typescript

function greet(user: [1]) { console.log(`Hello, ${user.name}`); }

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Anumber

BUser

Cstring

D{ name: string; age: number }

Attempts:

3 left

💡 Hint

Common Mistakes

Using a type alias name instead of inline type.

Using primitive types like string or number instead of object type.

Inline types are written directly in the parameter list using curly braces to describe the object shape.

3fill in blank

hard

Fix the error in the type alias declaration for a product with id and name.

Typescript

type Product = [1];

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A{ id: number; name: string }

B(id: number, name: string) => void

C[number, string]

Dnumber | string

Attempts:

3 left

💡 Hint

Common Mistakes

Using function type syntax instead of object type.

Using tuple or union types instead of object type.

The type alias for an object must use curly braces with property names and types, not function or tuple syntax.

4fill in blank

hard

Fill both blanks to create a type alias and use it in a function parameter.

Typescript

type [1] = { title: string; pages: number };
function printBook(book: [2]) { console.log(book.title); }

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ABook

BArticle

DMagazine

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for the type alias and parameter type.

Using inline type in one place and alias in another.

The type alias name must be the same in both declaration and usage to match the type.

5fill in blank

hard

Fill all three blanks to define a type alias, use it inline, and declare a variable with that type.

Typescript

type [1] = { x: number; y: number };
const point: [2] = { x: 10, y: 20 };
function logPoint(p: [3]) { console.log(`x: ${p.x}, y: ${p.y}`); }

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

APoint

DCoordinate

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for the type alias in different places.

Mixing inline types and type aliases inconsistently.

Using the same type alias name consistently for declaration, variable type, and function parameter ensures type safety and clarity.