How to filter an array - JavaScript

In this article we will learn how to filter an array.

It is very common to filter an array in JavaScript.

Problem

Now we have a problem, which is that we want to filter the array.

Imagine that we have an array with a set of numbers like this:

// Array
const array = [1, 2, 3, 4, 200, 300, 400]

And we want to delete the numbers above 100 to make it like this.

[1, 2, 3, 4]

How to solve this problem

Well, to solve this problem using filter method.

Filter an array using filter method

We can use filter to filter our array.

Example

// 1. Define an array
const array = [1, 2, 3, 4, 200, 300, 400];

// 3. Filter our array
const filter = array.filter(value => {

    // 4. If value more than 100
    if (value > 100) {

        // Don't add it to new array
        return false
    }

    // Otherwise add it to new array
    return true;
})

// Result:
console.log(filter);

Output

[ 1, 2, 3, 4 ]

How it works?

• First, we defined our array const array
• Second, we defined a new array const filter
• Third, we filter our array using filter method
• Then, we check if value is more than 100 or not

// 4. If value more than 100
if (value > 100) {

    // Don't add it to new array
    return false
}

// Otherwise add it to new array
return true;

• If value more than 100, don't add it into new array
• Otherwise add it.

Thank you for reading

Thank you for reading my blog. 🚀