Boolean type behavior in Typescript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a boolean variable with value true.

Typescript

let isActive: boolean = [1];

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

A"true"

Byes

C1

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around true, making it a string instead of a boolean.

Assigning numbers like 1 or 0 instead of true or false.

The boolean type in TypeScript accepts only true or false as values, not strings or numbers.

2fill in blank

medium

Complete the code to check if the variable is false.

Typescript

if ([1] === false) {
  console.log("It is false");
}

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

AisActive === false

B!isActive

CisActive == true

DisActive

Attempts:

3 left

💡 Hint

Common Mistakes

Writing the comparison twice like isActive === false === false.

Using negation !isActive when the code already compares to false.

To check if a variable equals false, use variable === false. Here, the if condition already compares to false, so just the variable name is needed.

3fill in blank

hard

Fix the error in the code to assign a boolean value correctly.

Typescript

let isDone: boolean = [1];

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

Afalse

B"false"

C0

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning the string "false" instead of the boolean false.

Using numbers like 0 or null which are not boolean values.

Boolean variables must be assigned true or false without quotes. Using strings or other types causes errors.

4fill in blank

hard

Fill both blanks to create a boolean expression that checks if x is true and y is false.

Typescript

if (x [1] true && y [2] false) {
  console.log("Condition met");
}

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

A===

B==

C!=

D!==

Attempts:

3 left

💡 Hint

Common Mistakes

Using loose equality == which can cause unexpected results.

Using inequality operators which check for difference, not equality.

Use the strict equality operator === to compare boolean values for exact match.

5fill in blank

hard

Fill all three blanks to create a boolean expression that checks if a is true and c is true.

Typescript

if ([1] [2] true && [3] === true) {
  console.log("All conditions met");
}

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

Aa

Bb

C===

Dc

Attempts:

3 left

💡 Hint

Common Mistakes

Using loose equality == instead of strict equality ===.

Mixing variable names or operators in wrong blanks.

Use the strict equality operator === to check if a and c are true.