In-depth analysis of JS frontend and backend technologies

 Koa JS

Introduction

The designers of Express.js developed KoaJS, an open-source, simple, and adaptable NodeJS web framework. KoaJS is referred to as the next-generation Node.js framework. It is described on the official website as a smaller, more expressive, more robust basis for web applications and APIs. It makes use of asynchronous functions to reduce the requirement for callbacks and improve error handling. It's core does not include any middleware. It offers an improved set of ways for speeding up and exciting the server-building process.

Features of KoaJS

• Modern and futuristic

It's based on the ES6 standard, which provides plenty of new classes and modules to make developing complicated applications easier. As a result, it assists developers in creating maintainable apps that hold up over time.

• Decreased resource utilization

It takes up less space. This allows developers to create middleware that is lighter and more efficient. They do, however, have the option of plugging in a number of modules to expand the system to meet the needs of varied projects.

• Better Error handling

The framework's built-in error detection helps developers avoid website crashes by catching all mistakes. Programmers can report errors using a simple 'try/catch' command without having to write any additional code. Error handling in KoaJS can also be customized by developers.

• Make use of a context object 

The unified object includes a number of handy methods and assessors that make it easy for developers to design web apps and APIs. This context combines the request and response into a single object with multiple methods for developing web apps and APIs.

 

Advantages of KoaJS

• Improved interoperability and robustness
• Extremely lightweight
• User-friendly
• Asynchronous codes are cleaner and more readable
• No callback hell

Limitations of KoaJS

• The community is quite small
• Express-style middleware is incompatible.
• It makes use of generators that are incompatible with any other Node.js framework middleware.

KoaJS Users

• Paralect
• Pubu
• Bulb
• GAPO
• Clovis

ReactJS

Introduction

React is a UI development library based on JavaScript. It is run by Facebook and an open-source developer community. React is widely utilized in web development, despite the fact that it is a library rather than a language. The library debuted in May 2013 and has since become one of the most popular frontend libraries for web development. It is for creating reusable user interface components that is declarative, efficient, and versatile. It's a component-based front-end library that's just responsible for the application's view layer.

Features of ReactJS

• JSX

JSX is a combination of HTML and JavaScript. JavaScript objects can be inserted into HTML elements. Because browsers do not support JSX, the code is transcompiled into JavaScript by the Babel compiler. JSX makes coding simple and straightforward.

•  Virtual DOM

It functions similarly to a one-way data binding. The complete UI is re-rendered in virtual DOM representation whenever any changes are made to the web application. Then it compares the old DOM representation to the new DOM representation. After that, the true DOM will only update the elements that have actually changed. This speeds up the application and eliminates memory waste.

 

• One-way Data Binding

It uses one-way data binding or unidirectional data flow. The child component's properties cannot return data to its parent component, but they can communicate with it to adjust the states based on the inputs. One-way data binding provides you with more control across the application. If the data flow occurs in the opposite way, additional characteristics are required. 

• Components

A ReactJS application consists of several components, each with its own logic and controls. These components are reusable, which makes it easier to keep the code clean while working on larger projects. 

•  Simplicity

It makes use of a JSX file, which makes the application easy to code and comprehend. It is a component-based approach, which means the code may be reused as needed. This makes it easy to use and understand.

•  Performance

It makes advantage of virtual DOM and only updates the portions that have changed. As a result, the DOM runs faster. Since the DOM runs in memory, we can create independent components, making the DOM run quicker.

Component Life-Cycle

Every component in React goes through a life cycle, from being generated and mounted in the DOM to being unmounted and destroyed. In a nutshell, this is what is known as the Component Lifecycle. There are three high-level elements to the component lifecycle:

• Mounting, when the component is first loaded into the DOM
• Updating, when the component updates due to a change in state or props
• Unmounting, When a component is deleted from the DOM

Lifecycle Methodologies

constructor()

In a class, the constructor is a method for initializing an object's state. It is automatically called when an object in a class is created. A React component's constructor is called before the component is mounted. You must call super(props) function before any other line when writing a React component's constructor. this.props will be undefined in the constructor if super(props) is not called, which might lead to errors.

render()

It is in charge of rendering the component to the user interface. It occurs while the component is being mounted and updated. It returns the JSX that is displayed in the UI, or null if the component has nothing to render. It cannot modify the component state.

componentDidMount()

It is called as soon as the component is mounted and ready. If you need to load data from a remote endpoint, this is the location to start making API calls. It can change the state of the component, but only before the browser updates the UI. This prevents the user from seeing any UI updates due to the double rendering. However, this may cause performance concerns.

componentDidUpdate()

Update the DOM in response to prop or state changes is the most prevalent use case. An infinite loop might result from incorrect use of setState(). To check for state or prop changes from the previous state, wrap it with a condition. This is to see if the props have changed from what they are right now.

componentWillUnmount()

Just before the component is unmounted and destroyed, it is called. If you need to undertake any cleanup work, this is the right place to do it.

shouldComponentUpdate()

It tells React whether or not a component is affected by state and prop changes. It is solely used for specific performance enhancements.

getDerivedStateFromProps()

In response to prop changes, it returns an object to update state. If there is no change in state, it can return null. This approach is only useful in rare circumstances where the state of a component is affected by changes in its props.

getSnapshotBeforeUpdate()

It's called just as the DOM is about to be changed. This can be useful when resizing the window during an asynchronous rendering.

Context API

Props are used to send data top-down (parent to child) in a typical React application, but this might be inconvenient for certain sorts of props (e.g. locale preference, UI theme) that are required by multiple components within an application. Context allows to pass data through our component trees, giving the components the ability to communicate and share data at different levels. 

Hooks

It allows you to access state and lifecycle capabilities of React without having to use classes. It allows you to connect function components to React state and lifecycle features. It should only be used in React functional components and only at the top level. They are backwards compatible, which implies there are no significant changes. It also doesn't take the place of your understanding of React ideas.

Props and State

Props are variables that a React component receives from its parent component. React’s data flow between components is uni-directional (from parent to child only). State, on the other hand, is still a set of variables that the component manages directly. State should not be changed directly, however it can be changed using the setState method ( ). Since state has an impact on the performance of your program, it should not be used excessively.

Babel

It is a JavaScript compiler and toolchain that is mostly used to turn ECMAScript 2015+ code into a backwards compatible version of JavaScript that can be utilized in both current and older browsers or environments. One of the best aspects of Babel is its compatibility with new features. It works with JSX and FLOW (Static type checker).

Webpack

Webpack, commonly known as module bundler, is a tool that compiles JavaScript modules. It creates a single file (or a few files) that runs your software from a huge number of files. It's not just for frontend development and also beneficial in backend development. It keeps an eye out for changes and repeats the activities. It can perform Babel transpilation to ES5, allowing you to leverage the most recent JavaScript features without having to worry about browser compatibility. It enables you to use require() for any files that are reliant. It has the ability to launch a development webserver.

Parcel

Parcel is an excellent tool for creating single and multi-page React applications. Fast Refresh provides a first-class development experience, and it supports JSX, TypeScript, Flow, and a variety of style approaches out of the box. It makes use of all of your computer's cores. Since everything is cached, you never have to write the same code twice. It's the same as utilizing watch mode, except it happens even if it is restarted.