Filter method in Javascript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to filter out numbers less than 5 from the array.

Javascript

const numbers = [1, 4, 6, 8];
const filtered = numbers.filter(num => num [1] 5);
console.log(filtered);

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

A===

B>

C<

D!==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' will keep numbers less than 5, which is the opposite.

Using '===' or '!==' compares equality, not greater or less.

The filter keeps numbers greater than 5, so we use '>' operator.

2fill in blank

medium

Complete the code to filter only even numbers from the array.

Javascript

const nums = [1, 2, 3, 4, 5];
const evens = nums.filter(n => n [1] 2 === 0);
console.log(evens);

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A%

B*

C/

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '/' divides but does not check remainder.

Using '*' or '+' does not help check even numbers.

The modulus operator '%' gives the remainder. Even numbers have remainder 0 when divided by 2.

3fill in blank

hard

Fix the error in the filter callback to keep strings longer than 3 characters.

Javascript

const words = ['cat', 'lion', 'dog', 'elephant'];
const longWords = words.filter(word => word.length [1] 3);
console.log(longWords);

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

A>

B<

C===

D!==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' keeps shorter words, which is wrong here.

Using '===' or '!==' checks equality, not length comparison.

We want words longer than 3, so use '>' operator to compare length.

4fill in blank

hard

Fill both blanks to filter numbers divisible by 3 from the array.

Javascript

const arr = [3, 4, 6, 7, 9];
const divisibleByThree = arr.filter(num => num [1] 3 [2] 0);
console.log(divisibleByThree);

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

A%

B===

C!==

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!== 0' keeps numbers not divisible by 3.

Using '>' does not check divisibility.

Use '%' to get remainder and '===' to check if remainder is zero for divisibility.

5fill in blank

hard

Fill all three blanks to filter words starting with letter 'a' (case insensitive).

Javascript

const words = ['Apple', 'banana', 'Avocado', 'cherry'];
const aWords = words.filter(word => word.[1](0).[2]() [3] 'a');
console.log(aWords);

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

AtoLowerCase

BtoUpperCase

C===

DcharAt

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'toUpperCase' on the whole word instead of the first letter.

Not converting case leads to missing words starting with uppercase 'A'.

Use 'charAt(0)' to get first letter, then 'toLowerCase()' to compare ignoring case.