Javascript Training in Brooklyn, NY

My advice is to always use const and only use let when you know you’ll need to reassign a value to that variable. If we know a value cannot be reassigned, it’s one less source for bugs. A variable is a value assigned to an identifier, so you can reference and use it later in the program. When we need to have a reference to a value, we assign it to a variable. The variable can have a name, and the value is what’s stored in a variable, so we can later access that value through the variable name.

  • JavaScript is an actively evolving language and has changed greatly over the years.
  • Learn modern JavaScript (ES2015+) from scratch, and practice in an intuitive environment.
  • Having previous experience with other programming languages might also help.

It sounds extremely simple, but booleans are used all the time in JavaScript programming, and they are extremely useful. Anything that needs to be “on” or “off”, “yes” or “no”, “true” or “false”, or which just has a temporary purpose, is usually a good fit for booleans. The easiest way to learn Programming concepts for absolute beginners step by step.


This means that a line of code is executed, then the next one is executed, and so on. Most of the time, JavaScript code is run synchronously. In this chapter we’ll go up one level by introducing classes. We talked about objects, which are one of the most interesting parts of JavaScript. We can retrieve the value of a property using 2 different syntaxes. As you can see, when we have multiple properties, we separate each property with a comma.

If you pass a string, it always evaluates to true unless it’s an empty string. You can use the following operators to compare two numbers, or two strings. After assignment and math operators, the third set of operators I want to introduce is conditional operators. Once you assign a value with some type to a variable, you can later reassign the variable to host a value of any other type without any issues. In practice, you will most likely keep a well defined style and adhere to what people commonly use, and enforce this using a linter or a style tool such as Prettier.

Learn Programming

JavaScript is an actively evolving language and has changed greatly over the years. In particular, the 6th edition of the language (sometimes known as ECMAScript 2015 or ES6), introduced in 2015, added many new features. JavaScript is a powerful programming language that can add interactivity to a website.

  • JavaScript is a powerful and flexible programming language.
  • You can set the value of a property when you define the object.
  • We first call the function, then we have a then() method that is called when the function ends.

It can start with a letter, the dollar sign $ or an underscore _, and it can contain digits. Using Unicode, a letter can be any allowed character, for example, an emoji ?. Whether you’re a beginner looking to get started in web development or an experienced programmer looking to expand your skills, this course has something for you. With clear explanations, practical examples, and hands-on exercises, you’ll be able to learn at your own pace and apply your new skills to real-world projects.

JavaScript Objects

The dollar sign is commonly used to reference DOM elements. Sometimes it’s hard to separate JavaScript from the features of the environment it is used in. JavaScript is also now widely used outside of the browser. The rise of Node.js in the last few years unlocked backend development, once the domain of Java, Ruby, Python, PHP, and more traditional server-side languages. This is a great short introductory course and Brad is an experienced developer who will walk you through all of this concepts in an easy to understand manner. This is a great short introductory course and Mosh is an experienced developer who will walk you through all of these concepts in an easy to understand manner.

JavaScript Lessons

Here we have a car object with a property named color, with value blue. This is the object literal syntax, which is one of the nicest things in JavaScript. Arrow functions are a recent introduction to JavaScript. The nested function cannot be called from the outside of the enclosing function. Just like with while loops, you can interrupt a for loop using break and you can fast forward to the next iteration of a for loop using continue.

Now that we saw how to work with const and let, I want to mention var. We have many different types in JavaScript, and we’ll talk about them in detail later on. In most cases, you can omit semicolons altogether from your programs without even thinking about it. Every line in a JavaScript program is optionally terminated using semicolons. In JavaScript, we can write a comment on a single line using //.

JavaScript Lessons