Top 10 Most Popular JavaScript Frameworks

Top 10 Most Popular JavaScript Frameworks

Top 10 Most Popular JavaScript Frameworks - Over the years there have been many JavaScript frameworks release and choosing one amongst them can be a challenge...

Top 10 Most Popular JavaScript Frameworks - Over the years there have been many JavaScript frameworks release and choosing one amongst them can be a challenge...

If you’re confused and you don’t know which one to choose or which is the right one for you, I’ve got you covered. In this blog, I’m going to list down the top 10 JavaScript Frameworks that you should be using to build web apps.

Here’s a list of frameworks I’ll be covering in this blog:

  1. AngularJS
  2. ReactJS
  3. VueJS
  4. jQuery
  5. BackboneJS
  6. NodeJS
  7. EmberJS
  8. MeteorJS
  9. PolymerJS
  10. Aurelia
10. JavaScript Frameworks: Aurelia

Aurelia is a toolbox of all the open source modern JavaScript modules that aids in web and mobile application advancement. It’s also called the “next-gen framework”. This framework has been gaining a lot of recognition ever since its launch. Companies like Fileee, Freska, Ordami and BTEK Software and over 800 websites make use of Aurelia.

Not to forget, Aurelia is the only framework that lets developers build components with plain, Vanilla TypeScript or JavaScript.

JavaScript Frameworks – Aurelia features

Below I’ve listed a few key features of Aurelia:
Multiple language support: Aurelia’s APIs are carefully designed to be consumed naturally from both today’s and tomorrow’s most useful web programming languages. Aurelia supports ES5, ES2015, ES2016 and Typescript which is very helpful and gives you high flexibilityModule framework: Rather than taking the monolithic framework approach, Aurelia is composed of smaller, focused modules. Use them together as a full-featured framework, or pick and choose to build a custom solution.Clean docs: Aurelia comes with a highly descriptive and helpful document set that aides all developers. It’s known for having a well-maintained documentation.Extensible HTML: Aurelia’s extensible HTML compiler lets you create custom HTML elements, add custom attributes to existing elements and control template generation, all with full support for dynamic loading, data binding and high-performance batched rendering.## 9. JavaScript Frameworks: Polymer

Polymer is an open source JavaScript library maintained by Google for building web applications using web components. Currently, over 3000 websites are using polymer, to name a few there is virustotal.com, rogers.com, zeplin.io and so on.

Unlike other JavaScript framework, Polymer is built to leverage the features that are present in the web to let developers build components. It was the very first library to allow interactive building applications by making use of web components.

JavaScript Frameworks – Polymer JS features

Below I’ve listed a few key features of Polymer:
Web components: Polymer is built on top of theidea of web components. Web components are a set of w3c standards which consists of several different web technologies including custom elements. These components are a part of the browser so you don’t need any third party tools and libraries like jQuery.One-way and two-way data binding: It provides both one-way and two-way data binding. Polymer is designed to support data that flows in one direction as well as bidirectional.Native browser: Polymer utilizes the native browser technologies instead of relying on custom JavaScript library. The polymer DOM layer is closest to the native JavaScript layer.Custom elements: It allows to create our own custom elements easily using the HTML, CSS, and JavaScript for adding interactions to the element. Polymer.js provides the simplest way to create custom HTML elements because its library is built on top of web standards API.## 8. JavaScript Frameworks: Meteor

Meteor is a free, open-source JavaScript framework written using NodeJS. It allows rapid prototyping and produces cross-platform code. It’s gaining popularity in the market with over 13,000 websites using Meteor. Websites like mtv.com, meteofrance.com and so on make use of Meteor to build their UI.

Below I’ve listed a few key features of Meteor:
Full stack: Meteor offers a full-stack solution for developing and deploying web applications. Meteor comes bundled with several built-in features, such as reactive templates, automatic CSS, etc.Smart packages: Building a login system for your application can be burdensome. But not with Meteor. Meteor packages make it easy to add features such as user accounts, JavaScript libraries like React and more. The best part is, adding these kinds of smart packages is easy, just a few keystrokes in the terminal and you have it. Real-time web apps: Meteor is the perfect solution for those looking to build real-time applications. All of the application’s layers from database to template update automatically. This means there is no need to refresh the page to see updates. And any changes to documents save instantly. This makes Meteor a perfect use-case for real-time collaboration.Single language development: Meteor allows using the same code on the front-end and the back-end as well, for mobile and web applications. It prevents developers from requiring to install and configure different libraries, module managers, APIs, drivers and more. This saves a lot of production time of developers as they do not need to perform context switching between server language and JavaScript.## 7. JavaScript Frameworks: Ember

Ember is an open source JavaScript web framework that lets developers build scalable single web page applications by incorporating the best practices into the framework. Ember was named the best of client-side JavaScript frameworks, leaving behind its main competitors, React and AngularJS. Currently, over 6000 websites are using ember. To name a few, nasa.gov, tutorialspoint.com, etc.

JavaScript Frameworks – Ember JS features

Below I’ve listed a few key features of Ember:
Future of web development: With the help of the Babel JavaScript transpiler, Ember allows developers to use future JavaScript standards and transpile them for use in today’s browsers. Don’t know what Babel is? Babel is a JavaScript transpiler that lets developers use next-generation JavaScript into their code now. Also, Babel benefits from numerous plugins, and is compatible with frameworks like Ember, Rails, Sails, and Meteor.Ember cli: Ember and Ember-CLI are two different things entirely, but neither would be totally whole without the other. Ember-CLI is a command line utility that comes along with the Ember framework’s software stack. Ember-CLI is a productivity rocket ship, with support for tools like CoffeeScript, Handlebars, LESS, and Sass.Ember template: Built into Ember’s UI are Ember’s templates, which are written with the Handlebars templating language. Handlebars is named for its use of double curly brackets and it allows developers to use way less code. Templates make a lot of features possible in Ember, like Components, Outlets, and Expressions.CoC: The sole purpose of the convention is the speed and the “Get Stuff Done” philosophy which is a massive boost for the startups who always battle hard to outpace their competitors. Ember has well-defined best practices for how it is structured. This means developers can focus more on their apps’ functionality and unique features, and less on reinventing the wheel with tedious code. There’s more building, and less blueprinting.## 6. JavaScript Frameworks: NodeJS

Node.js is a open source, server-side platform built on Google Chrome’s JavaScript Engine. The number of websites using NodeJS has crossed 84,000. It is one of the most downloaded, cross-platform runtime environments for executing JavaScript code.

JavaScript Frameworks – Node JS features

Below I’ve listed a few key features of Node.js:
Non-blocking: All APIs of Node.js library are asynchronous, that is, non-blocking. It essentially means a Node.js based server never waits for an API to return data. The server moves to the next API after calling it and a notification mechanism of Events helps the server to get a response from the previous API call.Single threaded: Node.js makes use of a single threaded model with event looping. The Event mechanism helps the server to respond in a non-blocking way, resulting in making the server highly scalable as opposed to traditional servers which create limited threads to handle requests. The single-threaded program used by Node.js can provide service to a much larger number of requests, as compared to traditional servers like Apache HTTP Server.Fast: NodeJS was built on Google Chrome’s JavaScript Engine called V8 engine. Google’s V8 JavaScript Engine makes sure that the Node.js library executes its code at lightning fast speeds.Data streaming: NodeJS applications never buffer any data, they just output the data in the form of data chunks. This way NodeJS provides faster services.## 5. JavaScript Frameworks: BackboneJS

BackboneJS is a lightweight JavaScript library that allows to develop and structure the client-side applications that run in a web browser. Unlike other frameworks, Backbone puts the developer in charge of choosing the right tool that works best for a given project. Currently, over half a million websites are making use of Backbone, this includes tumblr.com, espn.com, soundcloud.com and many more.

JavaScript Frameworks – Backbone JS features

Below I’ve listed a few key features of Backbone:
Separated business and UI logic: The single most important thing that Backbone can help you with, is keeping your business logic separate from your user interface. When the two are entangled, change is hard. But when logic doesn’t depend on UI, your interface becomes easier to work with.Event-driven communication: When a project grows, the jQuery declarations and callbacks gets more complex. The code becomes more cluttered. Backbone.js overcomes this problem by providing an event-driven communication between views and models.Less code: Conventions are a great way to introduce a common coding style without the need of coming up with an extensive set of coding standards. The more you stick to backbone conventions the less you have to code, and in turn, the code becomes more standardized and readable.Syncing with backend: All thanks to its excellent support for RESTful APIs, the models in BackboneJS can be easily tied to a back-end. If the API is designed correctly, backbone is already configured to access these directly for read, write, and delete operations.## 4. JavaScript Frameworks: jQuery

One of the oldest JS frameworks is the Jquery. This framework has been around for over 12 years and it’s still going strong. So, what is jQuery?

jQuery is a fast and concise JavaScript Library created by John Resig in 2006 with a nice motto, Write less, do more. It is a cross-platform JavaScript library designed to simplify the client-side scripting of HTML. Currently, over 19 million websites are using jQuery! Companies like WordPress, Facebook, Google, IBM and many others rely on jQuery to provide a one of a kind web browsing experience.

JavaScript Frameworks – jQuery features

Below I’ve listed a few key features of jQuery:
DOM Manipulation: It makes it extremely easy to manipulate DOM enabling developers to do amazing things and using best of their creativity through easy to learn API, which is built on the top JavaScript.Large community: The community of its contributors is more diverse and bigger than that of any other JavaScript library. It has extensive and comprehensive documentation. Not to forget that it’s continuously maintained and has been getting better and stronger.AJAX support: In short, AJAX (Asynchronous JavaScript and XML) is about loading data in the background and display it on the webpage, without reloading the whole page. jQuery provides several methods for AJAX functionality. With the jQuery AJAX methods, you can request text, HTML, XML, or JSON from a remote server using both HTTP Get and HTTP Post.Cross-browser support: The jQuery has cross-browser support, and works well in IE 6.0+, FF 2.0+, Safari 3.0+, Chrome and Opera 9.0+, etc.## 3. JavaScript Frameworks: Vue

Vue is an open source JavaScript framework for building creative UI. Integrating into projects that use other JavaScript libraries is simplified with Vue because it is designed to be adaptable. Currently, over 36,000 websites are using Vue. Companies like stackoverflow, playstation, etc. are relying on Vue for their websites UI.

JavaScript Frameworks – Vue JS features

Below I’ve listed few key features of VueJS:
Template: Vue.js offers HTML-based templates that bind the DOM with the Vue.js instance data. Vue.js compiles the templates into virtual DOM Render functions. A web developer can use template of the render functions and can replace the template with the render function.Small in size: The success of JavaScript framework depends on its size. The smaller the size is, the more it will be used. One of the greatest advantages of Vue.js is its small size. The size of this framework is 18–21KB.Adaptable: Vue allows the user to write his template in HTML file, JavaScript file, and pure JavaScript file using virtual nodes. This flexibility also makes it easy to understand for the developers of React.js, Angular.js, and any other new JavaScript framework. It is based on JavaScript framework and can be integrated into other applications built on JavaScript.Detailed docs: Developers always like to use the framework with detailed documentation because it is always easy for them to write their first application. The documentation with Vue.js is so comprehensive that any user who knows a little about JavaScript and HTML can develop his own application or web page.## 2. JavaScript Frameworks: ReactJS

React is another JavaScript library maintained by Facebook for building interactive and complex UI. It is one of the most trending frameworks with over 3 lakh websites implementing React in their UI. To name a few websites, we have Microsoft.com, yahoo.com and so on.

JavaScript Frameworks – React JS features

Below I’ve listed a few key features of ReactJS:
Virtual DOM: In React, for every DOM object, there is a corresponding “virtual DOM object.” A virtual DOM object is a representation of a DOM object, it creates a virtual copy of the original DOM. It’s a one-way data binding hence manipulating the virtual DOM is quick rather than updating the original DOM because nothing gets drawn onscreen. JSX: Instead of the usual JavaScript that’s used for templating, React utilizes JSX, a simple JavaScript that uses HTML quoting. You can also use HTML syntax to render subcomponents, or write in good old-fashioned JavaScript, meaning you have flexibility as you code, either way.Unidirectional data flow: React.js is designed in such a manner that it will only support data that is flowing downstream, in one flow. If the data has to flow in another direction, you will need additional features.Components: In React everything is treated as components, thus you can easily import component supported by React, instead of coding or building an entire feature you can import it and make use of it.## 1. JavaScript Frameworks: AngularJS

One of the most powerful, efficient, and open-source JavaScript frameworks is Angular. It’s impossible to not mention Angular in my Top 10 JavaScript Frameworks list. This framework is operated by the Google and is used for developing Single Page Application (SPA). This development framework is known primarily because it gives developers the best conditions for combining JavaScript with HTML and CSS. Over half a million websites like google.com, youtube.com, etc. are using Angular.

Below I’ve listed few key features of Angular:
MVC architecture: One of the most important features of AngularJS is the MVC or Model-View-Controller architecture. The MVC architecture is divided into three elements, i.e., the Model, View and Controller.Model: It is the lowest level of the MVC architecture where your data is stored.View: This element is responsible for showcasing all your data to the user.Controller: It is basically a software code that controls the entire interactions between the Model and View.2way binding: This is an amazing feature that sets AngularJS apart from other JavaScript frameworks. Angular Data-Binding builds a link between model and view. In a two-way data binding process, the View displays changes made in the Model and, the Model reflects changes made in the View.Single page app: With AngularJS framework, you can build fully responsive single page apps that can easily fit different screen sizes perfectly. Plus, these apps are also capable of offering an improved user experience as compared to other web apps. Since the AngularJS-based single page apps are rendered on the client side, they reduce the network traffic by decreasing the load on the web sever HTML UI: Another great feature of AngularJS is the fact that it uses the HTML language to build user interfaces. The HTML language is a common and declarative language with very short tags that are simple to understand. This leads to a more organized and simplistic UI. JavaScript interfaces are often more complicated to develop and organize. If you’re looking for a solution that’s quick, simple, and easy to use at a moment’s notice, then this could be it.
I hope you found this blog informative and knowledgeable. Let us know in the comment section which else framework you think could have made it to this list.

Also, check out our video on Top 10 JavaScript Frameworks and don’t forget to leave a comment if you have any queries regarding this topic.

What is JavaScript – All You Need To Know About JavaScript

What is JavaScript – All You Need To Know About JavaScript

In this article on what is JavaScript, we will learn the basic concepts of JavaScript.

After decades of improvement, JavaScript has become one of the most popular programming languages of all time. It all started in the year 1995 when Brendan Eich created JavaScript in a span of 10 days. Since then, it has seen multiple versions, updates and has grown to the next level.

Here’s a list of topics that I’ll be covering in this blog:

  1. What is JavaScript
  2. What can JavaScript do?
  3. JavaScript Frameworks
  4. The Big Picture: HTML, CSS & JavaScript
  5. Benefits of JavaScript
  6. Fundamentals of JavaScript
    VariablesConstantsData TypesObjectsArraysFunctionsConditional statementsLoopsSwitch case
What is JavaScript?

JavaScript is a high level, interpreted, programming language used to make web pages more interactive.

Have you ever thought that your website is missing something? Maybe it’s not engaging enough or it’s not as creative as you want it to be. JavaScript is that missing piece which can be used to enhance web pages, applications, etc to provide a more user-friendly experience.

What is JavaScript?

JavaScript is the language of the web, it is used to make the web look alive by adding motion to it. To be more precise, it’s a programming language that let’s you implement complex and beautiful things/design on web pages. When you notice a web page doing more than just sit there and gawk at you, you can bet that the web page is using JavaScript.

Feature of JavaScript

Scripting language and not Java: In fact, JavaScript has nothing to do with Java. Then why is it called “Java” Script? When JavaScript was first released it was called Mocha, it was later renamed to LiveScript and then to JavaScript when Netscape (founded JavaScript) and Sun did a license agreement. Object-based scripting language which supports polymorphism, encapsulation and to some extent inheritance as well.**Interpreted language: **It doesn’t have to be compiled like Java and C which require a compiler.JavaScript runs in a browser: You can run it on Google Chrome, Internet Explorer, Safari, etc. JavaScript can execute not only in the browser but also on the server and any device which has a JavaScript Engine.

What is JavaScript – Stackoverflow stats

Currently, we have 100s of programming languages and every day new languages are being created. Among these are few powerful languages that bring about big changes in the market and JavaScript is one of them.

JavaScript has always been on the list of popular programming languages. According to StackOverflow, for the 6th year in a row, JavaScript has remained the most popular and commonly used programming language.

What can JavaScript do?

JavaScript is mainly known for creating beautiful web pages & applications. An example of this is Google Maps. If you want to explore a specific map, all you have to do is click and drag with the mouse. And what sort of language could do that? You guessed it! It’s JavaScript.JavaScript can also be used in smart watches. An example of this is the popular smartwatch maker called Pebble. Pebble has created Pebble.js which is a small JavaScript Framework that allows a developer to create an application for the Pebble line of watches in JavaScript.

What is JavaScript – Applications of JavaScript
Most popular websites like Google, Facebook, Netflix, Amazon, etc make use of JavaScript to build their websites.Among things like mobile applications, digital art, web servers and server applications, JavaScript is also used to make Games. A lot of developers are building small-scale games and apps using JavaScript.## JavaScript Frameworks

One major reason for the popularity of JavaScript is the JavaScript Frameworks. Here’s a brief introduction of the most trending JavaScript frameworks :

  1. AngularJS is Google’s web development framework which provides a set of modern development and design features for rapid application development.

  2. ReactJS is another top JavaScript framework mainly maintained by Facebook and it’s behind the User Interface of Facebook and Instagram, showing off its efficiency in maintaining such high traffic applications.

What is JavaScript – JavaScript Frameworks

  1. MeteorJS is mainly used for providing back-end development. Using JavaScript on the back-end to save time and build expertise is one of the major ideas behind Meteor.

  2. jQuery can be used when you want to extend your website and make it more interactive. Companies like Google, WordPress and IBM rely on jQuery.

The Big Picture: HTML, CSS & JavaScript

Anyone familiar with JavaScript knows that it has something to do with HTML and CSS. But what is the relationship between these three? Let me explain this with an analogy.

What is JavaScript – HTML, CSS and JavaScript

Think of HTML (HyperText Markup Language) as the skeleton of the web. It is used for displaying the web.

On the other hand, CSS is like our clothes. We put on fashionable clothes to look better. Similarly, the web is quite stylish as well. It uses CSS which stands for Cascading Style Sheets for styling purpose.

Then there is JavaScript which puts life into a web page. Just like how kids move around using the skateboard, the web also motions with the help of JavaScript.

Benefits of JavaScript

There has to be a reason why so many developers love working on JavaScript. Well, there are several benefits of using JavaScript for developing web applications, here’s a few benefits:

It’s easy to learn and simple to implement. It is a weak-type programming language unlike the strong-type programming languages like Java and C++, which have strict rules for coding.

It’s all about being fast in today’s world and since JavaScript is mainly a client-side programming language, it is very fast because any code can run immediately instead of having to contact the server and wait for an answer.

Rich set of frameworks like AngularJS, ReactJS are used to build web applications and perform different tasks.

**Builds interactive websites: **We all get attracted to beautifully designed websites and JavaScript is the reason behind such attractive websites and applications.

JavaScript is an interpreted language that does not require a compiler because the web interprets JavaScript. All you need is a browser like Google Chrome or Internet Explorer and you can do all sorts of stuff in the browser.

JavaScript is platform independent and it is supported by all major browsers like Internet Explorer, Google Chrome, Mozilla Firefox, Safari, etc.

JavaScript Fundamentals

In this What is JavaScript blog, we’ll cover the following basic fundamentals of JavaScript
VariablesConstantsData TypesObjectsArraysFunctionsConditional statementsLoopsSwitch case## Variables

Variable is a name given to a memory location which acts as a container for storing data temporarily. They are nothing but reserved memory locations to store values.

What is JavaScript – Variables

To declare a variable in JavaScript use the ‘let’ keyword. For example:

let age;
age=22;

In the above example, I’ve declared a variable ‘age’ by using the ‘let’ keyword and then I’ve stored a value (22) in it. So here a memory location is assigned to the ‘age’ variable and it contains a value i.e. ’22’.

Constants

Constants are fixed values that don’t change during execution time.

To declare a constant in JavaScript use the ‘const’ keyword. For example:

const mybirthday;
mybirthday='3rd August'; 

Data types

You can assign different types of values to a variable such as a number or a string. In JavaScript, there are two categories of data types :

What is JavaScript – Data Types

Objects

An object is a standalone entity with properties and types and it is a lot like an object in real life. For example, consider a girl, whose name is Emily, age is 22 and eye-color is brown. In this example the object is the girl and her name, age and eye-color are her properties.

What is JavaScript – Objects example

Objects are variables too, but they contain many values, so instead of declaring different variables for each property, you can declare an object which stores all these properties.

To declare an object in JavaScript use the ‘let’ keyword and make sure to use curly brackets in such a way that all property-value pairs are defined within the curly brackets. For example:

let girl= {
name: 'Emily',
age: 22,
eyeColour: 'Brown'
};

In the above example, I’ve declared an object called ‘girl’ and it has 3 properties (name, age, eye colour) with values (Emily, 22, Brown).

Arrays

An array is a data structure that contains a list of elements which store multiple values in a single variable.

For example, let’s consider a scenario where you went shopping to buy art supplies. The list of items you bought can be put into an array.

What is JavaScript – Arrays example

To declare an array in JavaScript use the ‘let’ keyword with square brackets and all the array elements must be enclosed within them. For example:

let shopping=[];
shopping=['paintBrush','sprayPaint','waterColours','canvas'];

In the above example I’ve declared an array called ‘shopping’ and I’ve added four elements in it.

Also, array elements are numbered from zero. For example this is how you access the first array element:

shopping[0];		

Functions

A function is a block of organised, reusable code that is used to perform single, related action.

Let’s create a function that calculates the product of two numbers.

To declare a function in JavaScript use the ‘function’ keyword. For example:

function product(a, b) {
return a*b;
}

In the above example, I’ve declared a function called ‘product’ and I’ve passed 2 parameters to this function, ‘a’ and ‘b’ which are variables whose product is returned by this function. Now, in order to call a function and pass a value to these parameters you’ll have to follow the below syntax:

product(8,2);

In the above code snippet I’m calling the product function with a set of values (8 & 2). These are values of the variables ‘a’ and ‘b’ and they’re called as arguments to the function.

Conditional statements – if

Conditional statement is a set of rules performed if a certain condition is met. The ‘if’ statement is used to execute a block of code, only if the condition specified holds true.

What is JavaScript – if flowchart

To declare an if statement in JavaScript use the ‘if’ keyword. The syntax is:

if(condition) {
statement;
}

Now let’s look at an example:

let numbers=[1,2,1,2,3,2,3,1];
if(numbers[0]==numbers[2]) {
console.log('Correct!');
}

In the above example I’ve defined an array of numbers and then I’ve defined an if block. Within this block is a condition and a statement. The condition is ‘(numbers[0]==numbers[2])’ and the statement is ‘console.log(‘Correct!’)’. If the condition is met, only then the statement will be executed.

Conditional statements- Else if

Else statement is used to execute a block of code if the same condition is false.

What is JavaScript – Else-if flowchart

The syntax is:

if(condition) {
statement a;
}
else (condition) {
statement b;
}

Now let’s look at an example:

let numbers=[1,2,1,2,3,2,3,1];
if(numbers[0]==numbers[4] {
console.log("Correct!");
}
else {
console.log("Wrong, please try again");
}

In the above example, I’ve defined an if block as well as an else block. So if the conditions within the if block holds false then the else block gets executed. Try this for yourself and see what you get!

**Loops **

Loops are used to repeat a specific block until some end condition is met. There are three categories of loops in JavaScript :

  1. while loop
  2. do while loop
  3. for loop
While loop

While the condition is true, the code within the loop is executed.

What is JavaScript – while loop flowchart

The syntax is:

while(condition) {
loop code;
}

Now let’s look at an example:

let i=0;
while(i < 5) {
console.log("The number is " +i);
i++;
}

In the above example, I’ve defined a while loop wherein I’ve set a condition. As long as the condition holds true, the while loop is executed. Try this for yourself and see what you get!

Do while loop

This loop will first execute the code, then check the condition and while the condition holds true, execute repeatedly.

What is JavaScript – Do while loop flowchart

Refer the syntax to better understand it:

do {
loop code;
} while(condition);

This loop executes the code block once before checking if the condition is true, then it will repeat the loop as long as the condition holds true.

Now let’s look at an example:

do {
console.log("The number is " +i);
i++;
}
while(i > 5);

The above code is similar to the while loop code except, the code block within the do loop is first executed and only then the condition within the while loop is checked. If the condition holds true then the do loop is executed again.

For loop

The for loop repeatedly executes the loop code while a given condition is TRUE. It tests the condition before executing the loop body.

What is JavaScript – for loop flowchart

The syntax is:

for(begin; condition; step) {
loop code;
}

In the above syntax:

  • begin statement is executed one time before the execution of the loop code
  • condition defines the condition for executing the loop code
  • step statement is executed every time after the code block has been executed

For example:

for (i=0;i<5;i++) {
console.log("The number is " +i);
}

In the above example, I’ve defined a for loop within which I’ve defined the begin, condition and step statements. The begin statement is that ‘i=0’. After executing the begin statement the code within the for loop is executed one time. Next, the condition is checked, if ‘i<5’ then, the code within the loop is executed. After this, the last step statement (i++) is executed. Try this and see what you get!

Switch Case

The switch statement is used to perform different actions based on different conditions.

What is JavaScript – Switch case flowchart

Let’s look at the syntax for switch case:

switch(expression) {
case 1:
code block 1
break;
case 2:
code block 2
break;
default:
code block 3
break;
}

How does it work?

  • Switch expression gets evaluated once
  • Value of the expression is compared with the values of each case
  • If there is a match, the associated block of code is executed

Let’s try this with an example:

let games='football';
switch(games) {
case "throwball":
console.log("I dislike throwball!");
break;
case "football":
console.log("I love football!");
break;
case "cricket":
console.log("I'm a huge cricket fan!");
break;
default:
console.log("I like other games");
break;
}

In the above example the switch expression is ‘games’ and the value of games is ‘football’. The value of ‘games’ is compared with the value of each case. In this example it is compared to ‘throwball’, ‘cricket’ and ‘football’. The value of ‘games’ matches with the case ‘football’, therefore the code within the ‘football’ case is executed. Try this for yourself and see what you get!

With this, we come to the end of this blog. I hope you found this blog informative and I hope you have a basic understanding of JavaScript. In my next blog on JavaScript I’ll be covering in-depth concepts, so stay tuned.

Also, check out our video on JavaScript Fundamentals if you want to get started as soon as possible and don’t forget to leave a comment if you have any doubt and also, let us know whether you’d want us to create more content on JavaScript. We are listening!

Learn JavaScript in 60 Minutes | JavaScript Crash Course | JavaScript Tutorial |

This video on "JavaScript" will help you learn JavaScript basics and fundamental concepts in 60 minutes. This will provide you in-depth knowledge about the JavaScript fundamentals that will help you write your own code in JavaScript and build a website. This JavaScript tutorial covers following topics..

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JavaScript | How to use classes in JavaScript

JavaScript | How to use classes in JavaScript

Classes in JavaScript are a special syntax for its prototypical inheritance model that resembles class based inheritance in other object oriented languages. Classes are just special functions that can be declared to resembles classes in other languages. In JavaScript, we can have class declarations and class expressions, because they are just functions. So like all other functions, there are function declarations and function expressions. Classes serve a templates to create new objects.

Defining Classes

To declare a class, or make a class declaration, we use the class keyword to do so. For example, to declare a simple class, we can write:

class Person{
  constructor(firstName, lastName) {
    this.firstName= firstName;
    this.lastName = lastName;
  }
}

Class declarations aren’t hoisted so they can used before they are defined in the code, as the JavaScript interpreter will not automatically pull them up to the top. So the class above won’t work before it’s defined in the code like the following:

const person = new Person('John', 'Smith');
class Person{
  constructor(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }
}

We will get a ReferenceError if we run the code above.

We can also define a class by a class expression, which is an alternative syntax for defining a class. They can be named or unnamed. We can also assign a class to a variable like we do with functions. If we do that, we can reference the class by its name. For example, we can define:

let Person = class {
  constructor(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }
}

To get the name of the unnamed classes above, we can get the name with the name property, like so:

console.log(Person.name);


We can also undefined a named class like the following:


let Person = class Person2{
  constructor(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }
}

Then to get the name of the class, we can use the name property again. So we if we write:

console.log(Person.name)


we get Person2 logged.

The class body is defined with curly brackets. We define the class members inside the brackets. The body of the class is executed in strict mode, so everything defined in strict mode applies to the definition of a class, so we can’t define variables with out some keyword before it like var , let or const , and many other rules apply when you define a class. Classes in JavaScript also have a constructor method that lets us set fields when the object is instantiated with a class . Each class can only have one constructor method in it. If there’s more than one, then SyntaxError will be thrown. A constructor have to also call the super method to call the constructor of the super class inside if it the class extends a parent class.

Methods that aren’t declared static constitutes of the prototypical methods of the class. They are called after an object has been created by using the new keyword. For example, the following class have only prototypical methods:


class Person{
  constructor(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }
  get fullName(){
    return `${this.firstName} ${this.lastName}`  
  }
  sayHi(){
    return `Hi, ${this.firstName} ${this.lastName}`
  }
}

In the Person class above, fullName and sayHi are prototypical methods. They are called like this:

const person = new Person('Jane', 'Smith');
person.fullName() // 'Jane Smith'

Static methods are methods that can be called without creating an object from the class using the new keyword. For instance, we can have something like the following:


class Person {
  constructor(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }
  get fullName() {
    return `${this.firstName} ${this.lastName}`
  }
  sayHi() {
    return `Hi, ${this.firstName} ${this.lastName}`
  }
  static personCount() {
    return 3;
  }
}

We can call the personCount function without using the new keyword to create an instance of the class. So if we write:

Person.personCount

We get 3 returned.

The this value inside prototypical methods will be the value of the object. For static methods the value of this has the class that the static method is in as the value.

Getters and Setters

JavaScript classes can have getters and setter functions. Getters, as the name suggests, is a method that lets us get some data from a class. Setters are methods that gives us the ability to set some fields of the class. We denote getter functions with the get keyword and setters with the set keyword. For example, we can write a class that has getters and setters like the following:

class Person {
  constructor(firstName, lastName) {
    this._firstName = firstName;
    this._lastName = lastName;
  }
  get fullName() {
    return `${this.firstName} ${this.lastName}`
  }
  get firstName() {
    return this._firstName
  }
  get lastName() {
    return this._lastName
  }
  sayHi() {
    return `Hi, ${this.firstName} ${this.lastName}`
  }
  set firstName(firstName) {
    this._firstName = firstName;
  }
  set lastName(lastName) {
    this._lastName = lastName;
  }
}

Then when we use the new keyword to construct a Person object, we can use them in the following way:


const person = new Person('Jane', 'Smith');
person.firstName = 'John';
person.lastName = 'Doe';
console.log(person.firstName, person.lastName)

Since we have the getter and setter functions, we can use them to set the data directly to set the data for firstName and lastName of the Person class. In the setter functions, which start with the keyword set , what we assign to them get passed into the parameters and set in the member of the class. In the getter functions, which are denote by get we return the member values so that we can use them.

JavaScript Inheritance

In JavaScript, we can create classes where the properties can be included in the properties of a child class.

So, we can have a high-level class that contains the properties that are common to all the child classes, and the child class can have its own special properties that are not in any other classes.

For example, if we have an Animal class with the common properties and methods, like name and the eat method, then the Bird class can just inherit the common properties in the Animal class. They don’t have to be defined in the Bird class again.

We can write the following to do inheritance in JavaScript:

class Animal {
  constructor(name) {
    this.name = name;
  }
  eat() {
    console.log('eat');
  }
}
class Bird extends Animal {
  constructor(name, numWings) {
    super(name);
    this.numWings = numWings;
  }
}
const bird = new Bird('Joe', 2);
console.log(bird.name)
bird.eat();

In the example above, we have the parent class, Animal, that has the eat method, which all classes that extends from Animal will have, so they don’t have to define eat again.

We have the Bird class which extends the Animal class. Note that in the constructor of the Bird class, we have the super() function call to call the parent’s class constructor to populate the properties of the parent class in addition to the properties of the child class.

Classes cannot extend regular objects, which cannot be constructed with the new keyword. If we want to inherit from a regular object, we have to use the Object.setPrototypeOf function to set a class to inherit from a regular object. For example:

const Animal = {
  eat() {
    console.log(`${this.name} eats`);
  }
};
class Cat{
  constructor(name) {
    this.name = name;
  }
}
class Chicken{
  constructor(name) {
    this.name = name;
  }
}
Object.setPrototypeOf(Cat.prototype, Animal);
Object.setPrototypeOf(Chicken.prototype, Animal);
let cat = new Cat('Bob');
let chicken = new Chicken('Joe');
cat.eat();
chicken.eat();

If we run the example code above, we have see Bob eats and Joe eats logged because we have inherited the eat function from the Animal object.

this Keyword

The this keyword allows us to access the current object’s properties inside an object, unless you’re using arrow functions.

As we can see from the above example, we can get the properties of the instance of the child and the parent class in the object.

Mixins

We can use mixins to do multiple inheritance in JavaScript. Mixins are templates for creating classes. We need mixins to do multiple inheritance because JavaScript classes can only inherit from one super class, so multiple inheritance isn’t possible.

For example, if we have a base class, we can define mixins to incorporate the members from multiple classes into one by composing the mixins by calling one and then pass the returned result into the next one as the argument, an so on, like so:

class Base {
  baseFn() {
    console.log('baseFn called');
  }
}
let classAMixin = Base => class extends Base {
  a() {
    console.log('classAMixin called');
  }
};
let classBMixin = Base => class extends Base {
  b() {
    console.log('classBMixin called');
  }
};
class Bar extends classAMixin(classBMixin(Base)) {}
const bar = new Bar();
bar.baseFn()
bar.a()
bar.b()

In the code above, we have the Base class which we pass into the classBMixin to get the b function into the Base class, then we call the classAMixin by passing in the result of classBMixin(Base) into the argument of the classAMixin to return the a function from classAMixin into the Base class and then return the whole class with all the functions from all the classes incorporated into one.

If we call all the functions above like we did by creating an instance of the Bar object and then call the baseFn , a and b functions, then we get:

baseFn called
classAMixin called
classBMixin called

This means that we have all the functions from the mixins incorporated into the new Bar class.

In JavaScript, classes are just syntactic sugar to make the prototypical inheritance of JavaScript clearer by letting us structure the code in a way that’s more like typical inheritance class based object oriented inheritance pattern. This means that we write classes to and use the new keyword to create objects from the classes, but underneath the syntactic sugar, we are still using prototypical inheritance to extend objects. We can extend classes from objects and we can also use mixins to do multiple inheritance in of JavaScript classes.