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A Beginner’s Guide to JavaScript

JavaScript is one of the most popular programming languages in the world. It’s used in a variety of applications, especially in web development. However, learning JavaScript can be challenging if it’s the first programing language you tackle. But don’t worry. Even though it comes with a steep learning curve, JavaScript is a highly rewarding and dynamic language to learn.

This article outlines the essential information you should know before diving any deeper into the language itself. As a bonus, we’ll share some of the most commonly used terminologies in the program to help you kickstart your learning experience.

What Is JavaScript?

JavaScript is a programming language created to run in a web browser. Due to its nature, it’s also known as a client-side language. If you want to design an interactive web page, JavaScript should be your go-to language of choice. Some adjectives that describe JavaScript include:

  • High-level. This means you can code JS without access to host computer details, including memory, processor, pointers, etc.
  • Untyped. There are two types of programming languages – typed and untyped. The former requires programmers to declare variable types. Untyped languages are more flexible about defining types. JS can pass a number or a string to the same function, but more on the terminology later.
  • Dynamic. JavaScript allows programmers to change object structure or add new code while running the program.
  • Interpreted. JavaScript’s codes are run by an interpreter software, which is a part of the web browser. The interpreter reads the code and converts it to machine instructions so it can be run.
  • Standardized. JS’s official name is ECMAScript, a standard programming language that makes sure JavaScript is operable in any browser.

Why Learn JavaScript?

If you’re an aspiring web developer, learning JavaScript is a great step towards a new career. It’s one of the most commonly used and dynamic languages. In fact, JS is used to create an array of web, tablet, mobile devices, and desktop experiences. JavaScript is the essential code behind many games, apps, and even web page layouts requiring interaction with users. YouTube, Netflix, Google Maps, your phone’s operating system, and even your smart TV have JavaScript interpreters installed.

JavaScript is also one of the most natural languages to learn. Anyone can do so, with or without a Ph.D. Needless to say, tons of job opportunities are open for JavaScript developers of all levels. You could start applying for JS jobs within a year of learning, as this is how long it takes to grasp the basics on average.

JavaScript Disadvantages

Before you start learning JavaScript, it’s essential to familiarize yourself with a few of its limitations.

  • Performance. JS doesn’t come with the same level of performance as other traditional programming languages. Writing complex programs in JS would just be too slow. However, JS is mainly used for performing simple tasks inside a browser, so this issue shouldn’t be a significant restriction.
  • Potentially steep learning curve. JS is a scripting language and requires a deep understanding of the core concepts, server and client-side objects, and more. Without the proper knowledge, writing advanced scripts in JS would be virtually impossible.
  • It has no access to databases.
  • JS doesn’t allow reading or writing files.
  • It can’t be used for networking applications due to a lack of support.

Even though JavaScript has limitations, it’s still the most popular programming language for web development. The vivid community and a plethora of frameworks and libraries only go in its favor. But more on that below.

JavaScript Frameworks

JavaScript frameworks help developers build interactive applications with ease. Developers don’t have to start from scratch for every single line of code but can rely on a functional base to achieve their goals faster. As for JS, that base consists of code libraries that compile codes eliciting specific functionalities for a particular app. JavaScript has different frameworks, and they all serve different purposes.

For example, creating a new website from scratch would take a tremendous amount of work. Thanks to the frameworks, developers can get a skeleton for the website to support its overall structure.

Some popular frameworks include React, Vue, NextS, and Angular.

IDE and Libraries

Integrated Development Environment (IDE) or JavaScript IDE allows developers to run functions in their browsers using a keyboard or mouse. The IDE provides quick application programming as it eliminates the need for configuring many utilities manually.

On the other hand, libraries are compilations of code snippets developers can use to run JS functions. Plenty of code lines are run repeatedly for the same tasks, so the JS community developed the frameworks and libraries to make programming easier.

Now that we’ve covered the basic information about what JavaScript is and how it can be used, it’s time to tackle the programming language from up close.

Popular JavaScript libraries include Bootstrap and jQuery.

IDE and Libraries

An Introduction to JavaScript’s Syntax and Terminology

Here are some terms you’ll need to grasp as you start exploring JavaScript.

White Space

White space refers to JS characters used to provide vertical and horizontal space between other characters.

Case Sensitive

JavaScript is case-sensitive. This means the variables, keywords, functions, and other identifiers need to be typed with consistent letter capitalization.

Literals

Literals refer to values written in the source code. Literals can be assigned to a string, Boolean, numeric, array, or other constructs and are considered their syntactic representations.

Comments

Many programming languages support the comment feature. JavaScript supports comments to add information or annotate a code. They can be used on single- or multiline codes. Comments are added by inserting “//” before single code lines or “/*” before and “*/” after multiple lines.

Semicolons

Semicolons are used to end the lines in JavaScript. However, JS interpreters, which are computer programs that convert high-level language code into a machine format, can do that for you.

Values

Values represent the common data types in JS, like strings and numbers. For example, “thanks” and “7” are values, the former being a string and the latter being a number.

Identifiers

An identifier in JavaScript is a sequence of code characters that identifies a function, variable, or property. In JS, identifiers are case-sensitive, may contain Unicode letters and digits, but never start with the latter.

Variables

Variables are values assigned to identifiers. Once developers name a variable, they can search for it and quickly access the value stored under its name. Before using variables, they have to be declared as “let,” “var,” or “const,” where the latter can’t be reassigned a new value, but the first two can. Many JavaScript developers use “const” more to avoid bugs. However, if the value is going to be changed later on, “var” and “let” should be used instead.

Expressions

Expressions are JavaScript units that the JS engine evaluates, then returns a value. There are different types of expressions, including primary, arithmetic, string, or logical expressions. Some complex expressions can also involve functions, objects, and arrays.

Types

There are two main types in JS: primitive and object types. Primitive types include strings, numbers, Booleans, and symbols. Objects represent a collection of methods and properties. They include a number, a string, a Boolean, undefined, or null. Programmers can assign a value to a specific variable, then reassign that variable to another value. But note that variables in JavaScript are untyped.

Objects

Objects in JS are non-primitive values, including numbers, strings, Boolean, symbols, null, and undefined values. We pass objects by references. All objects have Methods, Properties, Inheritance, and Classes. You can consider functions and arrays as objects in practical terms.

Strings

Strings in JavaScript store character sequences inside single or double quotes. You can use an addition operator (+) to join two strings together. We can define strings with the help of template literals. They make multiline strings simpler and provide a straightforward way to interpolate expressions and variables into strings.

Arrays

The term “arrays” refers to a collection of elements. Acting as objects, arrays can hold values of different types. They are also multi-dimensional, meaning one array can be put into another, making them great for creating a matrix.

Arrays

Operators

JavaScript programmers use operators to combine simple expressions into more complex ones. We classify operators following the operands they work with. Some can work with one, but most of them work with two. Only one operator can work with three operands. Check the list below to see what operators are used in JS. Don’t be surprised if you get random Algebra class flashbacks.

  • Addition
  • Subtraction
  • Division
  • Remainder
  • Exponentiation
  • Multiplication
  • Conditionals
  • Comparison

Loops

Loops are used to repeat blocks of codes and are part of JS’s control structures. The most common loops are “while” loops, “for” loops, and “for..of” loops.

Functions

Functions are the building blocks of JavaScript and feature a self-contained block of code. In JS, we can define functions inside other functions. However, the nested function needs to be called only from the inside of the enclosing function, never from the outside.

Variable Scope

A scope represents a set of variables visible to one section of the program. There are global, block, and function scopes in JavaScript. When a variable is defined outside of a function, its scope is global, and it’s available everywhere in the program.

These are some of the most popular terms you’ll encounter as you start exploring the dynamic world of JavaScript. Fear not – everything will make more sense once you start getting some practice. For now, it’s enough to have an idea of what’s ahead.

Ready to Learn JavaScript?

JavaScript is a golden ticket to the web developing world. If you have some programming experience, learning JS won’t be too challenging, but first-time programming language learners should be prepared for a steeper learning curve. Fortunately, the thriving JS community has developed many frameworks and libraries to make coding more dynamic and straightforward, especially for beginners. Hopefully, our guide has given you with a better understanding of what JavaScript is, how it works, and the basic terminology around it.

By interactivated • on November 20, 2021

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