Book Image

JavaScript from Beginner to Professional

By : Laurence Lars Svekis, Maaike van Putten, Codestars By Rob Percival
4 (5)
Book Image

JavaScript from Beginner to Professional

4 (5)
By: Laurence Lars Svekis, Maaike van Putten, Codestars By Rob Percival

Overview of this book

This book demonstrates the capabilities of JavaScript for web application development by combining theoretical learning with code exercises and fun projects that you can challenge yourself with. The guiding principle of the book is to show how straightforward JavaScript techniques can be used to make web apps ranging from dynamic websites to simple browser-based games. JavaScript from Beginner to Professional focuses on key programming concepts and Document Object Model manipulations that are used to solve common problems in professional web applications. These include data validation, manipulating the appearance of web pages, working with asynchronous and concurrent code. The book uses project-based learning to provide context for the theoretical components in a series of code examples that can be used as modules of an application, such as input validators, games, and simple animations. This will be supplemented with a brief crash course on HTML and CSS to illustrate how JavaScript components fit into a complete web application. As you learn the concepts, you can try them in your own editor or browser console to get a solid understanding of how they work and what they do. By the end of this JavaScript book, you will feel confident writing core JavaScript code and be equipped to progress to more advanced libraries, frameworks, and environments such as React, Angular, and Node.js.
Table of Contents (19 chapters)
16
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17
Index

Array methods

We have seen arrays already—they can contain multiple items. We have also seen quite a few built-in methods on arrays, like shift() and push(). Let's look at a few more in the following sections.

Performing a certain action for every item

There is a reason we are starting with this method. You might be thinking of loops at this point, but there is a built-in method that you can use to execute a function for every element in the array. This is the forEach() method. We mentioned this briefly in Chapter 6, Functions, but let's consider it in some more detail. It takes the function that needs to be executed for every element as input. Here you can see an example:

let arr = ["grapefruit", 4, "hello", 5.6, true];
function printStuff(element, index) {
  console.log("Printing stuff:", element, "on array position:", index);
}
arr.forEach(printStuff);

This code snippet will write to the console:

...