filter() Method

This chapter delves into the intricacies of the filter() method, elucidating its syntax, applications, and how it facilitates the creation of refined arrays.

filter()

The filter() method selects elements that meet a particular condition. Let's decipher the syntax:

Here's what we need to know about the filter() method:

It does not alter the original array;
It iterates over the original array element by element;
It returns a new array;
Elements are added to the new array if they satisfy the callback condition;
If the callback returns true, the element is included; otherwise, it is omitted.

Examples

The true prowess of the filter() method becomes apparent when applied to diverse scenarios. Let's delve into some illustrative examples:

Example 1: Filtering Odd Numbers

In this example, the filter() method creates an array (oddNumbers) comprising only odd numbers from the original array.


              123456
            
const numbers = [15, 22, 37, 41, 58, 67, 72];

const oddNumbers = numbers.filter((number) => {
  return number % 2 !== 0;
});
console.log(oddNumbers); // Output: 15, 37, 41, 67

Example 2: Filtering Products by Price Range

Here, the filter() method is utilized to extract products with prices below $500, creating a new array (affordableProducts).

1. What does the `filter()` method do?

2. What is a key characteristic of the `filter()` method?

3. In the example below, what should be the condition so that the `numbersGreaterThan20` array would contain numbers greater than 20?

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Seção 5. Capítulo 3