The JavaScript Beginner’s Handbook 2020 Edition

Whether you are an experienced programmer or not, this website is intended for everyone who wishes to learn the JavaScript programming language. Everything is as you expect, and how it works in most programming languages. Normally methods are defined on the object instance, not on the class. When the object is initialized, the constructor method is called with any parameters passed. Even arrays or functions are, under the hood, objects, so it’s very important to understand how they work. Any value that’s not of a primitive type (a string, a number, a boolean, a symbol, null, or undefined) is an object.

JavaScript Lessons

What started as a tiny language inside the browser is now the most popular language in the world. I believe it’s a great choice for your first programming language ever. This is an interactive learning environment where you will learn JavaScript by doing hundreds of challenges and five certification algorithm challenges. In this article, I will provide a list of free online resources where you can start learning JavaScript.

Advanced Functions

In this module we will explore what APIs are, and how to use some of the most common APIs you’ll come across often in your development work. JavaScript is one of the most popular modern web technologies! As your JavaScript skills grow, your websites will enter a new dimension of power and creativity. You can learn more in MDN’s JavaScript learning area, as well as in other parts of MDN. In JavaScript, a boolean value is one that can either be TRUE or FALSE. If you need to know “yes” or “no” about something, then you would want to use the boolean function.

You’ve seen this stuff already in the course, but only in passing — here we’ll discuss it all explicitly. Modern JavaScript is considered a safe programming language. It never provides low-level access to the memory or CPU as it was made for the browsers that don’t require it. The capabilities of this language highly rely on the environment it runs in. For example, Node.js includes functions allowing JavaScript to write and read arbitrary files, implement network requests, and so on.

Solving common JavaScript problems

And like regular functions, we can only return one value. Template literals are also great because they provide an easy way to interpolate variables and expressions into strings. Until 2015, var was the only way we could declare a variable in JavaScript. Today, a modern codebase will most likely just use const and let. There are some fundamental differences which I detail in this post but if you’re just starting out, you might not care about them.

JavaScript Lessons

The big difference with regular functions is when they are used as object methods. In this Programming with Mosh course, you will learn about JavaScript basics including conditions, loops, functions, objects, arrays, and ES6 features. The Odin Project has a beginner JavaScript course in the Foundations section. You will learn the basics including conditions, loops, functions, objects, arrays, and ES6. Const does not mean “constant” in the way some other languages like C mean. In particular, it does not mean the value cannot change – it means it cannot be reassigned.

How to remove an item from an array

Learn TypeScript step by step in an interactive environment. Main course contains 2 parts which cover JavaScript as a programming language and working with a browser. Business Computer Skills offers a variety of Javascript training classes in Brooklyn, NY. Get the professional training you need to take your Javascript skills to the next level. Our instructor led training is a cost effective and convenient learning platform for busy professionals. Training is available at over 350 locations nationwide and Online.

JavaScript Lessons

Rejecting a promise means ending it with an error (which results in calling the catch() method in whatever uses it). Resolving a promise means to complete it successfully (which results in calling the then() method in whatever uses it). Now, to be able to use this syntax, the doSomething() function implementation must be a little bit special. We define a function that accepts a callback parameter, which is a function. The function containing the console.log(‘inside the function’) line will be executed after 2 seconds. However, there are times when you cannot just wait for a line of code to execute.


There is a special method called constructor() that we can use to initialize the class properties when we create a new object instance. This is the reason why regular functions are often used as object methods. More advanced expressions involve objects, functions, and arrays, and I’ll introduce them later. Comments are one of the most important parts of any program, in any programming language.

In JavaScript, most things are objects, from core JavaScript features like strings and arrays to the browser APIs built on top of JavaScript. You can even create your own objects to encapsulate related functions and variables into efficient packages. Here we teach object theory and syntax in detail, look at how to create your own objects, and explain what JSON data is and how to work with it. The course assumes that you are familiar with the basics such as variables, functions, arrays, objects, classes as well as some HTML & CSS experience. The two types of functions are very similar, so you might ask why arrow functions were introduced.

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