Lesson 19 - Advanced Array Methods In JavaScript

In the previous lesson, Arrow Functions And Modern Event Handling In JavaScript, we introduced arrow functions. We already know that they offer us a shorter syntax and maintain the context of the this keyword in classes. We also showed a little hack how to avoid the that variable when handling DOM events and keep the element that triggered the event. Today, we're going to continue with arrow functions and learn how to use them to work with arrays.

Advanced Array Methods In JavaScript

Now let's look at methods that allow arrow functions to be used when working with arrays. Some came up with ES6, some have been here since ES5 and were initially designed to receive a function. Let's show them.

filter()

This method is used when we need to filter certain items from an array. The filter() method takes a function as a parameter that is automatically called for each item of the array. In this function, we return true if the item passed as a parameter meets our criteria. The filter() method then stores the matching items to a new array and returns it.

Example

Here's an example where we want to select only those numbers that are divisible by 2:

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