Arrow functions in Javascript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an arrow function that adds two numbers.

Javascript

const add = (a, b) => [1];

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

Aa * b

Ba + b

Ca - b

Da / b

Attempts:

3 left

💡 Hint

Common Mistakes

Using subtraction or multiplication instead of addition.

Forgetting to include both parameters.

The arrow function should return the sum of a and b, so use 'a + b'.

2fill in blank

medium

Complete the code to create an arrow function that returns the square of a number.

Javascript

const square = x => [1];

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

Ax * x

Bx + x

Cx / 2

Dx - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Adding the number to itself instead of multiplying.

Dividing or subtracting instead of multiplying.

To get the square, multiply the number by itself using 'x * x'.

3fill in blank

hard

Fix the error in the arrow function that returns the length of a string.

Javascript

const length = str => [1];

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Astr.length

Bstr.length()

Clength(str)

Dstr.size

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses after length like a function call.

Using incorrect property names like size.

In JavaScript, string length is accessed as a property without parentheses: 'str.length'.

4fill in blank

hard

Fill both blanks to create an arrow function that filters an array for numbers greater than 10.

Javascript

const filterLarge = arr => arr.filter(num => num [1] [2]);

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

A>

B10

C<

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' for the comparison.

Using the wrong number for comparison.

To filter numbers greater than 10, use 'num > 10' inside the filter.

5fill in blank

hard

Fill all three blanks to create an arrow function that maps an array to uppercase strings and filters those starting with 'A'.

Javascript

const process = arr => arr.map(str => str.[1]()).filter(str => str.[2](0) === [3]);

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

AtoUpperCase

BcharAt

C'A'

DtoLowerCase

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'toLowerCase' instead of 'toUpperCase'.

Using incorrect methods to get the first character.

Comparing to the wrong character.

Use 'toUpperCase()' to convert strings, 'charAt(0)' to get first letter, and compare to 'A'.