Fresh object literals vs variable assignment behavior in Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a fresh object literal assigned to obj.

Typescript

const obj = [1];

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

Aundefined

B[]

Cnull

D{}

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets [] instead of curly braces {}

Assigning null or undefined instead of an object

Using {} creates a fresh empty object literal in TypeScript.

2fill in blank

medium

Complete the code to assign obj2 to the same object as obj1.

Typescript

const obj1 = {};
const obj2 = [1];

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

Aobj1

B{}

Cnull

Dundefined

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning a new object literal instead of the existing variable

Assigning null or undefined

Assigning obj2 = obj1 makes both variables reference the same object.

3fill in blank

hard

Fix the error in the code to correctly copy properties from source to target without sharing the same object.

Typescript

const source = { a: 1 };
const target = [1];
// Now target and source are separate objects

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

A{ ...source }

Bsource

CObject.assign(source)

Dsource = {}

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning source directly instead of copying

Using Object.assign incorrectly without target object

Using the spread operator { ...source } creates a fresh object copying properties from source.

4fill in blank

hard

Complete the code to create a new object copy with all properties from original and add a new property id with value 5.

Typescript

const original = { name: 'Alice' };
const copy = [1] , { id: 5 };

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

A{ ...original }

B+

C...

D,

Attempts:

3 left

💡 Hint

Common Mistakes

Using plus (+) to combine objects

Using spread operator incorrectly outside object literal

Use the spread operator inside an object literal and separate properties with a comma.

5fill in blank

hard

Fill all three blanks to create a fresh object result that copies data, overrides count to 10, and adds a method show that logs count.

Typescript

const data = { count: 3 };
const result = {
  [1],
  count: [2],
  show() { console.log(this.[3]); }
};

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

A...data

B10

Ccount

Ddata.count

Attempts:

3 left

💡 Hint

Common Mistakes

Using data.count inside the method instead of this.count

Not overriding the count property correctly

Spread data to copy properties, override count with 10, and use this.count inside the method to access the property.