How To Migrate From jQuery To Subsequent.js

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When jQuery appeared in 2006, a variety of builders and organizations began to undertake it for his or her initiatives. The potential for extending and manipulating the DOM that the library provides is nice, and we even have many plugins so as to add conduct to our pages in case we have to do duties that aren’t supported by the jQuery principal library. It simplified a variety of the work for builders, and, at that second, it made JavaScript a strong language to create internet purposes or Single Web page Purposes.

The results of jQuery reputation is measurable nonetheless immediately: Virtually 80% of the preferred web sites of the world nonetheless use it. A few of the the reason why jQuery is so in style are:

It helps DOM manipulation.
It offers CSS manipulation.
Works the identical on all internet browsers.
It wraps HTML occasion strategies.
Simple to create AJAX calls.
Simple to make use of results and animations.

Through the years, JavaScript modified so much and added a number of options that we didn’t have previously. With the re-definition and evolution of ECMAScript, a number of the functionalities that jQuery supplied have been added to the usual JavaScript options and supported by all the online browsers. With this taking place, a number of the conduct jQuery provides was not wanted anymore, as we’re in a position to do the identical issues with plain JavaScript.

However, a brand new mind-set and designing consumer interfaces began to emerge. Frameworks like React, Angular or Vue enable the builders to create internet purposes primarily based on reusable practical parts. React, i.e., works with the “digital DOM”, which is a DOM illustration within the reminiscence, whereas jQuery interacts straight with the DOM, in a much less performant method. Additionally, React provides cool options to facilitate the event of sure options, corresponding to state administration. With this new method and the recognition that Single Web page Purposes began to achieve, a variety of builders began to make use of React for his or her internet software initiatives.

And entrance finish improvement advanced much more, with frameworks created on high of different frameworks. That’s the case, for instance, of Subsequent.js. It’s an open-source React framework that gives options to generate static pages, create server-side rendered pages, and mix each varieties in the identical software. It additionally permits creating serverless APIs inside the identical app.

There’s a curious situation: Though these frontend frameworks are increasingly in style through the years, jQuery continues to be adopted by a overwhelming majority of internet pages. One of many the reason why this occurs is that the share of internet sites utilizing WordPress is admittedly excessive, and jQuery is included within the Content material Administration System. Another excuse is that some libraries, like Bootstrap, have a dependency on jQuery, and there are some ready-to-use templates that use it and its plugins.

However one more reason for this quantity of internet sites utilizing jQuery is the price of migrating an entire internet software to a brand new framework. It’s not simple, it’s not low cost and it’s time-consuming. However, in the long run, working with new instruments and applied sciences brings a variety of advantages: Wider help, group help, higher developer expertise, and ease of getting folks engaged on the undertaking.

There are numerous situations the place we don’t want (or don’t need) to observe the structure that frameworks like React or Subsequent.js impose on us, and that’s okay. Though, jQuery is a library that incorporates a variety of code and options that aren’t wanted anymore. Most of the options jQuery provides might be achieved utilizing trendy JavaScript native capabilities, and possibly in a extra performant method.

Let’s talk about how we may cease utilizing jQuery and migrate our web site right into a React or Subsequent.js internet software.

Outline The Migration Technique

Do We Want A Library?

Relying on the options of our internet software, we may even have the case the place a framework just isn’t actually wanted. As talked about earlier than, a number of jQuery options have been included (or a minimum of a really related one) to the newest internet commonplace variations. So, contemplating that:

$(selector) sample from jQuery might be changed with querySelectorAll().

As a substitute of doing:


We are able to do:


Now we have now the property Aspect.classList if we wish to manipulate CSS lessons.

As a substitute of doing:


We are able to do:


Many animations might be finished straight utilizing CSS, as an alternative of implementing JavaScript.

As a substitute of doing:


We are able to do:

component.classList.take away(‘disguise’);

And apply some CSS styling:

.present {
transition: opacity 400ms;

.disguise {
opacity: 0;

Now we have now addEventListener perform if we wish to deal with occasions.

As a substitute of doing:

$(selector).on(eventName, eventHandler);

We are able to do:

component.addEventListener(eventName, eventHandler);

As a substitute of utilizing jQuery Ajax, we will use XMLHttpRequest.

As a substitute of doing:

kind: ‘POST’,
url: ‘/the-url’,
knowledge: knowledge

We are able to do:

var request = new XMLHttpRequest();‘POST’, ‘/the-url’, true);
request.setRequestHeader(‘Content material-Sort’, ‘software/x-www-form-urlencoded; charset=UTF-8’);

For extra particulars, you may check out these Vanilla JavaScript Code Snippets.

Determine Elements

If we’re utilizing jQuery in our software, we must always have some HTML content material that’s generated within the internet server, and JavaScript code that provides interactivity to the web page. We’re in all probability including occasion handlers on web page load, that may manipulate the DOM when the occasions occur, in all probability updating the CSS or the model of the weather. We may be calling backend companies to execute actions, that may have an effect on the DOM of the web page, and even reload it.

The thought could be to refactor the JavaScript code dwelling within the pages and create React parts. It will assist us to hitch associated code and compose parts that might be half of a bigger composition. By doing this we can even be capable to have higher dealing with of the state of our software. Analyzing the frontend of our software, we must always divide it into components devoted to a sure process, so we will create parts primarily based on that.

If we have now a button:

<button id=”btn-action”>Click on</button>

With the next logic:

var $btnAction = $(“#btn-action”);

$btnAction.on(“click on”, perform() {
alert(“Button was clicked”);

We are able to migrate it to a React Part:

import React from ‘react’;

export default class ButtonComponent extends React.Part {
constructor(props) {

handleButtonClicked() {
alert(“Button was clicked”);

render() {
return (
<button onClick={this.handleButtonClicked.bind(this)}>
Click on

However we must also consider how the migration course of might be achieved since our software is working and getting used, and we don’t wish to have an effect on it (or, a minimum of, have an effect on it as little as doable).

Good Migration

migration is one the place all of the components of the appliance are totally migrated to the brand new framework or know-how. This may be the best situation for our software since we might maintain in sync all of the components, and we might be utilizing a unified device and a novel referred model.

and full migration normally features a full re-write of the code of our app, and that is smart. If we construct an app from scratch, we have now the potential for deciding what path we wish to take with the brand new code. We may use a recent standpoint over our current programs and workflow, and create a complete new app with the data that we have now at this second, extra full than the one we had after we first created our internet software.

However an entire rewrite has some issues. To begin with, it requires a variety of time. The larger the appliance is, the extra time we might want to rewrite it. One other downside is the quantity of labor, and quantity of builders, that it takes. And, if we don’t do a progressive migration, we have now to consider how a lot time our software might be unavailable.

Usually, an entire rewrite might be achieved with small initiatives, initiatives that don’t change steadily, or purposes that aren’t so important for our enterprise.

Quick Migration

One other method is dividing the appliance into components or items. We migrate the app half by half, and we launch these components when they’re prepared. So, we have now migrated components of our software out there for the customers, and coexisting with our current manufacturing app.

With this gradual migration, we ship separated options of our undertaking in a sooner solution to the customers, since we don’t have to attend for the whole software to be re-written. We additionally get sooner suggestions from the customers, which permits us to detect bugs or points earlier.

However a gradual migration drives us to have completely different instruments, libraries, dependencies, and frameworks. Or we may even need to help completely different variations from the identical device. This prolonged help may deliver conflicts to our software.

We may even have issues if we’re making use of insurance policies within the world scope since every one of many migrated components may work otherwise, however being affected by the code that set world parameters to our system. An instance of that is using a cascade logic for CSS styling.

Think about we work with completely different variations of jQuery throughout our internet software as a result of we added functionalities from newer variations to the modules which have been created later. How sophisticated would it not be emigrate all our app to a more moderen model of jQuery? Now, think about the identical situation however migrating to a totally completely different framework like Subsequent.js. That may be sophisticated.

Frankenstein Migration

Denys Mishunov wrote an article on Smashing Journal presenting a substitute for these two migration concepts, attempting to get one of the best of the earlier two approaches: The Frankenstein Migration. It bases the migration course of in two principal parts: Microservices and Internet Elements.

The migration course of consists of an inventory of steps to observe:

1. Determine Microservices

Primarily based on our app code, we must always divide it into impartial components which can be devoted to at least one small job. If we’re fascinated with utilizing React or Subsequent.js, we may hyperlink the idea of microservices to the completely different parts that we have now.

Let’s take into consideration a grocery checklist software for instance. Now we have an inventory of issues to buy, and an enter so as to add extra issues to the checklist. So, if we wish to cut up our app into small components, we may take into consideration an “merchandise checklist” part and an “add merchandise”. Doing this, we will separate the performance and markup associated to every a type of components into completely different React parts.

To corroborate the parts are impartial, we must always be capable to take away considered one of them from the app, and the opposite ones shouldn’t be affected by that. If we get an error when eradicating the markup and performance from a service, we’re not appropriately not figuring out the parts, or we have to refactor the way in which our code works.

2. Enable Host-to-Alien Entry

“Host” is our current software. “Alien” is the one we’ll begin creating, with the brand new framework. Each ought to work independently, however we must always present entry from Host to Alien. We must always be capable to deploy any of the 2 purposes with out breaking the opposite one, however protecting the communication between them.

3. Write An Alien Part

Re-write a service from our Host software into our Alien software, utilizing the brand new framework. The part ought to observe the identical precept of independence that we talked about earlier than.

Let’s return to the grocery checklist instance. We recognized an “add merchandise” part. With jQuery, the markup of the part will look one thing like this:

<enter class=”new-item” />

And the JavaScript/jQuery code so as to add the objects to the checklist might be one thing like this:

var ENTER_KEY = 13;

$(‘.new-item’).on(‘keyup’, perform (e) {
var $enter = $(e.goal);
var val = $enter.val().trim();

if (e.which !== ENTER_KEY || !val) {

// code so as to add the merchandise to the checklist


As a substitute of that, we will create a AddItem React part:

import React, {Part} from ‘react’

export default class AddItem extends Part {
state = ”

handleSubmit = e => {
const textual content = e.goal.worth.trim()
if (e.which === 13) {
// code so as to add the merchandise to the checklist

handleChange = e => this.setState({textual content: e.goal.worth})

render() {
return (
kind=”textual content”
worth={this.state.textual content}
onKeyDown={this.handleSubmit} />

4. Write Internet Part Wrapper Round Alien Service

Create a wrapper part that imports our simply created Alien service and renders it. The thought is to create a bridge between the Host app and the Alien app. Understand that we may wish a package deal bundler to generate JavaScript code that works in our present software since we might want to copy our new React parts and make them work.

Following the grocery checklist instance, we will create an AddItem-wrapper.js file within the Host undertaking. This file will comprise the code that wraps our already created AddItem part, and creates a customized component with it:

import React from “../alien/node_modules/react”;
import ReactDOM from “../alien/node_modules/react-dom”;
import AddItem from “../alien/src/parts/AddItem”;

class FrankensteinWrapper extends HTMLElement {
connectedCallback() {
const appWrapper = doc.createElement(“div”);

<HeaderApp />,


customElements.outline(“frankenstein-add-item-wrapper”, FrankensteinWrapper);

We must always deliver the required node modules and parts from the Alien software folders since we have to import them to make the part work.

5. Change Host Service With Internet Part

This wrapper part will exchange the one within the Host software, and we’ll begin utilizing it. So, the appliance in manufacturing might be a mixture of Host parts and Alien wrapped parts.

In our instance Host software, we must always exchange:

<enter class=”new-item” />



<script kind=”module” src=”js/AddItem-wrapper.js”></script>

6. Rinse And Repeat

Undergo steps 3, 4, and 5 for every one of many recognized microservices.

7. Swap To Alien

Host is now a group of wrapper parts that embody all the online parts we created on the Alien software. As we transformed all of the recognized microservices, we will say that the Alien software is completed and all of the companies have been migrated. We simply have to level our customers to the Alien software now.

The Frankenstein Migration technique works as a mixture of each the Good and the Quick approaches. We migrate the whole software however releasing the completely different parts when they’re finished. So, they’re sooner out there for use and evaluated by the customers.

Now we have to contemplate, although, that we’re performing some over-work with this method. If we wish to use the parts we create for our Alien software, we have now to create a wrapper part to incorporate within the Host app. This makes us spend time growing the code for these wrapper parts. Additionally, by utilizing them in our Host software, we’re duplicating the inclusion of code and dependencies, and including code that may have an effect on the efficiency of our software.

Strangler Utility

One other method we will take is the Legacy Utility Strangulation. We determine the perimeters of our current internet software, and every time we have to add functionalities to our app we do it utilizing a more moderen framework till the previous system is “strangled”. This method helps us to cut back the potential danger we will experiment whereas migrating an app.

To observe this method, we have to determine completely different parts, as we do in Frankenstein Migration. As soon as we divide our app into completely different items of associated crucial code, we wrap them in new React parts. We don’t add any extra conduct, we simply create React parts that render our current content material.

Let’s see an instance for extra clarification. Suppose we have now this HTML code in our software:

<div class=”accordion”>
<div class=”accordion-panel”>
<h3 class=”accordion-header”>Merchandise 1</h3>
<div class=”accordion-body”>Textual content 1</div>
<div class=”accordion-panel”>
<h3 class=”accordion-header”>Merchandise 2</h3>
<div class=”accordion-body”>Textual content 2</div>
<div class=”accordion-panel”>
<h3 class=”accordion-header”>Merchandise 3</h3>
<div class=”accordion-body”>Textual content 3</div>

And this JavaScript code (we already changed jQuery capabilities with new JavaScript commonplace options).

const accordions = doc.querySelectorAll(“.accordion”);
for (const accordion of accordions) {
const panels = accordion.querySelectorAll(“.accordion-panel”);
for (const panel of panels) {
const head = panel.querySelector(“.accordion-header”);
head.addEventListener(‘click on’, () => {
for (const otherPanel of panels) {
if (otherPanel !== panel) {
otherPanel.classList.take away(‘accordion-expanded’);

This can be a widespread implementation of an accordion part for JavaScript. As we wish to introduce React right here, we have to wrap our current code with a brand new React part:

perform Accordions() {
useEffect(() => {
const accordions = doc.querySelectorAll(“.accordion”)
for (const accordion of accordions) {
const panels = accordion.querySelectorAll(“.accordion-panel”)
for (const panel of panels) {
const head = panel.querySelector(“.accordion-header”)
head.addEventListener(“click on”, () => {
for (const otherPanel of panels) {
if (otherPanel !== panel) {
otherPanel.classList.take away(“accordion-expanded”)
}, [])

return null

ReactDOM.render(<Accordions />, doc.createElement(“div”))

The part just isn’t including any new conduct or function. We use componentDidMount as a result of the part has been mounted within the doc. That’s the reason the render technique returns null, as a render technique is required and we don’t wish to modify our current DOM.

So, we didn’t add any new performance to our current app, however we launched React with out altering its conduct. To any extent further, every time we add new options or modifications to our code, we’ll do it utilizing the newer chosen framework.

Shopper-side Rendering, Server-side Rendering, Or Static Technology?

Subsequent.js provides us the potential for selecting how we wish to render every web page of our internet software. We are able to use the client-side rendering that React already provides us to generate the content material straight within the consumer’s browser. Or, we will render the content material of our web page within the server utilizing server-side rendering. Lastly, we will create the content material of our web page at construct time utilizing static era.

In our software, we must be loading and rendering code on web page load, earlier than we begin interacting with any JavaScript library or framework. We could also be utilizing a server-side rendering programming language or know-how, corresponding to ASP.NET, PHP, or Node.js. We are able to get benefit of Subsequent.js options and exchange our present rendering technique with the Subsequent.js server-side rendering technique. Doing this, we maintain all of the conduct inside the identical undertaking, that works underneath the umbrella of our chosen framework. Additionally, we maintain the logic of our principal web page and the React parts throughout the identical code that generates all of the wanted content material for our web page.

Let’s take into consideration a dashboard web page for instance. We are able to generate all of the preliminary markup of the web page at load time, within the server, as an alternative of getting to generate it with React within the consumer’s internet browser.

const DashboardPage = ({ consumer }) => {
return (

// Consumer knowledge


export const getServerSideProps = async ({ req, res, params }) => {
return {
props: {
consumer: getUser(),

export default DashboardPage

If the markup that we render on web page load is predictable and is predicated on knowledge that we will retrieve at construct time, static era could be a good selection. Producing static belongings at construct time will make our software sooner, safer, scalable, and simpler to take care of. And, in case we have to generate dynamic content material on the pages of our app, we will use React’s client-side rendering to retrieve info from companies or knowledge sources.

Think about we have now a weblog web site, with many weblog posts. If we use Static Technology, we will create a generic [blog-slug].js file in our Subsequent.js software, and including the next code we might generate all of the static pages for our weblog posts at construct time.

export const getStaticPaths = async () => {
const blogPosts = await getBlogPosts()

const paths ={ slug }) => ({
params: {

return {
fallback: false,

export const getStaticProps = async ({ params }) => {
const { slug } = params

const blogPost = await getBlogPostBySlug(slug)

return {
props: {
knowledge: JSON.parse(JSON.stringify(blogPost)),

Create An API Utilizing API Routes

One of many nice options Subsequent.js provides is the chance to create API Routes. With them, we will create our personal serverless capabilities utilizing Node.js. We are able to additionally set up NPM packages to increase the performance. A cool factor about that is that our API will go away in the identical undertaking/app as our frontend, so we received’t have any CORS points.

If we keep an API that is known as from our internet software utilizing jQuery AJAX performance, we may exchange them utilizing API Routes. Doing this, we’ll maintain all of the codebase of our app in the identical repository, and we’ll make the deployment of our software less complicated. If we’re utilizing a third-party service, we will use API Routes to “masks” the exterior URLs.

We may have an API Route /pages/api/get/[id].js that returns knowledge that we use on our web page.

export default async (req, res) => {
const { id } = req.question

strive {
const knowledge = getData(id)
} catch (e) {
res.standing(500).json({ error: e.message })

And name it from the code of our web page.

const res = await fetch(`/api/get/${id}`, {
technique: ‘GET’,

if (res.standing === 200) {
// Do one thing
} else {
console.error(await res.textual content())

Deploy to Netlify

Netlify is an entire platform that can be utilized to automate, handle, construct, take a look at, deploy and host internet purposes. It has a variety of options that make trendy internet software improvement simpler and sooner. Some Netlify highlights are:

World CDN internet hosting platform,
Serverless capabilities help,
Deploy previews primarily based on Github Pull Requests,
Prompt rollbacks,
Position-based entry management.

Netlify is a good platform to handle and host our Subsequent.js purposes, and it’s fairly easy to deploy an online app with it.

To begin with, we have to maintain monitor of our Subsequent.js app code in a Git repository. Netlify connects to GitHub (or the Git platform we want), and every time a change is launched to a department (a commit or a Pull Request), an automated “construct and deploy” process might be triggered.

As soon as we have now a Git repository with the code of our app, we have to create a “Netlify Website” for it. To do that, we have now two choices:

Utilizing Netlify CLI
After we set up the CLI (npm set up -g netlify-cli) and log into our Netlify account (ntl login), we will go to the foundation listing of our software, run ntl init and observe the steps.
Utilizing Netlify internet app
We must always go to Connect with our Git supplier, select our software’s repository from the checklist, configure some construct choices, and deploy.

For each strategies, we have now to contemplate that our construct command might be subsequent construct and our listing to deploy is out.

Lastly, the Important Subsequent.js plugin is put in mechanically, which is able to enable us to deploy and use API routes, dynamic routes, and Preview Mode. And that is it, we have now our Subsequent.js software up and operating in a quick and secure CDN internet hosting service.


On this article, we evaluated web sites utilizing jQuery library, and we in contrast them with new frontend frameworks like React and Subsequent.js. We outlined how we may begin a migration, in case it advantages us, to a more moderen device. We evaluated completely different migration methods and we noticed some examples of situations that we may migrate to Subsequent.js internet software initiatives. Lastly, we noticed find out how to deploy our Subsequent.js software to Netlify and get it up and operating.

Additional Studying and Assets

Frankenstein Migration: Framework-Agnostic Method
Eradicating jQuery from frontend
Getting Began with Subsequent.js
Find out how to Deploy Subsequent.js Websites to Netlify
Subsequent.js articles in Netlify Weblog

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