Devil  Moya

Devil Moya


How to Create Server Side Rendered React application using Next.js

Setting up a server side rendered app with the default code generated by Create React App is not easy. You have to do lots of changes to the default code to get anything working. Getting it to work exactly the way you want is even harder, so developers came up with some solutions. One of the best options is Next.js.

In this story, we will build an address book app, which uses those libraries, plus React Bootstrap, which has great integration with those libraries above to create forms. To start we need to run Next.js CLI to scaffold the app. We run npx create-next-app to create the app project folder with the initial files. The app will have a home page to display the contacts and let us open a modal to add a contact. There will be a table that displays all the contacts and Edit and Delete buttons on each row to edit or delete each contact. The contacts will store in a central Redux store to store the contacts in a central place, making them easy to access. React Router will be used for routing. Contacts will be saved in the back end spawned using the JSON server package.

For form validation, then you need to use a third-party library. Formik and Yup work great together to allow us to take care of most form validation needs. Formik let us build the forms and display the errors, and handle form value changes, which is another thing we have to do all my hand otherwise. Yup let us write a schema for validating our form fields. It can check almost anything, with common validation code like email and required fields available as built-in functions. It can also check for fields that depend on other fields, like the postal code format depending on the country. Bootstrap forms can be used seamlessly with Formik and Yup.

Once that is done, we have to install some libraries. To install the libraries we mentioned above, we run npm i axios bootstrap formik react-bootstrap react-redux react-router-dom yup . Axios is the HTTP client that we use for making HTTP requests to back end. react-router-dom is the package name for the latest version of React Router.

Now that we have all the libraries installed, we can start building the app. We create a store folder and create a file called actionCreator.js in it and add the following:

import { SET_CONTACTS } from './actions';

const setContacts = (contacts) => {
    return {
        type: SET_CONTACTS,
        payload: contacts

export { setContacts };

This is the action creator for creating the action for storing the contacts in the store.

We create another file called actions.js in the same folder and add:


export { SET_CONTACTS };

This just have the type constant for dispatching the action.

Then in the store folder, we create index.js and add:

import { contactsReducer } from "./reducers";
import { createStore, combineReducers } from "redux";

const addressBookApp = combineReducers({
  contacts: contactsReducer,

const makeStore = (initialState, options) => {
  return createStore(addressBookApp, initialState);

export { makeStore };

We will use it in the main entry point file, which will be called _app.js in the pages folder to allow us to use the same Redux store in this multi-page, server side rendered app.

Then we make a file called reducers.js , and add:

import { SET_CONTACTS } from './actions';

function contactsReducer(state = {}, action) {
    switch (action.type) {
        case SET_CONTACTS:
            state = JSON.parse(JSON.stringify(action.payload));
            return state;
            return state

export { contactsReducer };

This is the reducer where we store the contacts that we dispatch by calling the prop provided by the mapDispatchToProps function in our components.

Next we add some code files to the pages folder.

In index.js , we replace what is existing with the following:

import React from "react";
import Head from "next/head";
import { Router, Route } from "react-router-dom";
import { createMemoryHistory as createHistory } from "history";
import Navbar from "react-bootstrap/Navbar";
import Nav from "react-bootstrap/Nav";
import HomePage from "./HomePage";
import { contactsReducer } from "../store/reducers";
import { Provider } from "react-redux";
import { createStore, combineReducers } from "redux";

const history = createHistory();

const addressBookApp = combineReducers({
  contacts: contactsReducer,

const store = createStore(addressBookApp);

const Home = () => (
      <title>Address Book</title>
    <div className="App">
      <Router history={history}>
        <Navbar bg="primary" expand="lg" variant="dark">
          <Navbar.Brand href="#home">Address Book App</Navbar.Brand>
          <Navbar.Toggle aria-controls="basic-navbar-nav" />
          <Navbar.Collapse id="basic-navbar-nav">
            <Nav className="mr-auto">
              <Nav.Link href="/">Home</Nav.Link>
        <Route path="/" exact component={HomePage} />
    <style jsx>{`
      .App {
        text-align: center;

export default Home;

This is where we add the navigation bar and show our routes routed by the React Router. In the styles element, we replace the existing code with:

.App {
  text-align: center;

to center some text.

Next we build our contact form. This is the most logic heavy part of our app. We create a file called ContactForm.js in the components folder and add:

import React from 'react';
import { Formik } from 'formik';
import Form from 'react-bootstrap/Form';
import Col from 'react-bootstrap/Col';
import InputGroup from 'react-bootstrap/InputGroup';
import Button from 'react-bootstrap/Button';
import * as yup from 'yup';
import { COUNTRIES } from '../helpers/exports';
import PropTypes from 'prop-types';
import { addContact, editContact, getContacts } from '../helpers/requests';
import { connect } from 'react-redux';
import { setContacts } from '../store/actionCreators';

const schema = yup.object({
  firstName: yup.string().required('First name is required'),
  lastName: yup.string().required('Last name is required'),
  address: yup.string().required('Address is required'),
  city: yup.string().required('City is required'),
  region: yup.string().required('Region is required'),
  country: yup.string().required('Country is required').default('Afghanistan'),
  postalCode: yup
    .when('country', {
      is: 'United States',
      then: yup.string().matches(/^[0-9]{5}(?:-[0-9]{4})?$/, 'Invalid postal code'),
    .when('country', {
      is: 'Canada',
      then: yup.string().matches(/^[A-Za-z]\d[A-Za-z][ -]?\d[A-Za-z]\d$/, 'Invalid postal code'),
  phone: yup
    .when('country', {
      is: country => ["United States", "Canada"].includes(country),
      then: yup.string().matches(/^[2-9]\d{2}[2-9]\d{2}\d{4}$/, 'Invalid phone nunber')
  email: yup.string().email('Invalid email').required('Email is required'),
  age: yup.number()
    .required('Age is required')
    .min(0, 'Minimum age is 0')
    .max(200, 'Maximum age is 200'),

function ContactForm({
}) {
  const handleSubmit = async (evt) => {
    const isValid = await schema.validate(evt);
    if (!isValid) {
    if (!edit) {
      await addContact(evt);
    else {
      await editContact(evt);
    const response = await getContacts();
return (
    <div className="form">
        initialValues={contact || {}}
        }) => (
            <Form noValidate onSubmit={handleSubmit}>
                <Form.Group as={Col} md="12" controlId="firstName">
                  <Form.Label>First name</Form.Label>
                    placeholder="First Name"
                    value={values.firstName || ''}
                    isInvalid={touched.firstName && errors.firstName}
                  <Form.Control.Feedback type="invalid">
                <Form.Group as={Col} md="12" controlId="lastName">
                  <Form.Label>Last name</Form.Label>
                    placeholder="Last Name"
                    value={values.lastName || ''}
                    isInvalid={touched.firstName && errors.lastName}
<Form.Control.Feedback type="invalid">
                <Form.Group as={Col} md="12" controlId="address">
                      value={values.address || ''}
                      isInvalid={touched.address && errors.address}
                    <Form.Control.Feedback type="invalid">
                <Form.Group as={Col} md="12" controlId="city">
                    value={ || ''}
                    isInvalid={ &&}
<Form.Control.Feedback type="invalid">
                <Form.Group as={Col} md="12" controlId="region">
                    value={values.region || ''}
                    isInvalid={touched.region && errors.region}
                  <Form.Control.Feedback type="invalid">
<Form.Group as={Col} md="12" controlId="country">
                    value={ || ''}
                    isInvalid={touched.region &&}>
                    { => <option key={c} value={c}>{c}</option>)}
                  <Form.Control.Feedback type="invalid">
<Form.Group as={Col} md="12" controlId="postalCode">
                  <Form.Label>Postal Code</Form.Label>
                    placeholder="Postal Code"
                    value={values.postalCode || ''}
                    isInvalid={touched.postalCode && errors.postalCode}
<Form.Control.Feedback type="invalid">
<Form.Group as={Col} md="12" controlId="phone">
                    value={ || ''}
                    isInvalid={ &&}
<Form.Control.Feedback type="invalid">
<Form.Group as={Col} md="12" controlId="email">
                    value={ || ''}
                    isInvalid={ &&}
<Form.Control.Feedback type="invalid">
<Form.Group as={Col} md="12" controlId="age">
                    value={values.age || ''}
                    isInvalid={touched.age && errors.age}
<Form.Control.Feedback type="invalid">
              <Button type="submit" style={{ 'marginRight': '10px' }}>Save</Button>
              <Button type="button" onClick={edit ? onCancelEdit : onCancelAdd}>Cancel</Button>

ContactForm.propTypes = {
  edit: PropTypes.bool,
  onSave: PropTypes.func,
  onCancelAdd: PropTypes.func,
  onCancelEdit: PropTypes.func,
  contact: PropTypes.object

const mapStateToProps = state => {
  return {
    contacts: state.contacts,
const mapDispatchToProps = dispatch => ({
  setContacts: contacts => dispatch(setContacts(contacts))

export default connect(

We use Formik to facilitate building our contact form here, with our Boostrap Form component nested in the Formik component so that we can use Formik’s handleChange , handleSubmit , values , touched and errors parameters. handleChange is a function that let us update the form field data from the inputs without writing the code ourselves. handleSubmit is the function that we passed into the onSubmit handler of the Formik component. The parameter in the function is the data we entered, with the field name as the key, as defined by the name attribute of each field and the value of each field as the value of those keys. Notice that in each value prop, we have ||'' so we do not get undefined values and prevent uncontrolled form warnings from getting triggered.

To display form validation messages, we have to pass in the isInvalid prop to each Form.Control component. The schema object is what Formik will check against for form validation. The argument in the required function is the validation error message. The second argument of the matches , min and max functions are also validation messages.

The parameter of the ContactForm function are props, which we will pass in from the HomePage component that we will build later. The handleSubmit function checks if the data is valid, then if it is then it will proceed to saving according to whether it is adding or editing a contact. Then when saving is successful we set the contacts in the store and call onSave prop, which is a function to close the modal the form is in. The modal will be defined in the home page.

mapStateToProps is a function provided by React Redux so that we can map the state directly to the props of our component as the function name suggests. mapDispatchToProps allows us to call function in the props of the component called setContacts to dispatch the action as we defined in actionCreators.js .

Next we create a file called exports.js after creating the helpers folder, and put:

export const COUNTRIES = [
  "Antigua &amp; Barbuda",
  "Bosnia &amp; Herzegovina",
  "British Virgin Islands",
  "Burkina Faso",
  "Cape Verde",
  "Cayman Islands",
  "Cook Islands",
  "Costa Rica",
  "Cote D Ivoire",
  "Cruise Ship",
  "Czech Republic",
  "Dominican Republic",
  "El Salvador",
  "Equatorial Guinea",
  "Falkland Islands",
  "Faroe Islands",
  "French Polynesia",
  "French West Indies",
  "Guinea Bissau",
  "Hong Kong",
  "Isle of Man",
  "Kyrgyz Republic",
  "Netherlands Antilles",
  "New Caledonia",
  "New Zealand",
  "Papua New Guinea",
  "Puerto Rico",
  "Saint Pierre &amp; Miquelon",
  "San Marino",
  "Saudi Arabia",
  "Sierra Leone",
  "South Africa",
  "South Korea",
  "Sri Lanka",
  "St Kitts &amp; Nevis",
  "St Lucia",
  "St Vincent",
  "St. Lucia",
  "Timor L'Este",
  "Trinidad &amp; Tobago",
  "Turks &amp; Caicos",
  "United Arab Emirates",
  "United Kingdom",
  "United States",
  "United States Minor Outlying Islands",
  "Virgin Islands (US)",

These are countries for the countries field in the form.

Then we make a file called requests.js in the same folder, and add:

const APIURL = 'http://localhost:3000';
const axios = require('axios');

export const getContacts = () => axios.get(`${APIURL}/contacts`);

export const addContact = (data) =>`${APIURL}/contacts`, data);

export const editContact = (data) => axios.put(`${APIURL}/contacts/${}`, data);

export const deleteContact = (id) => axios.delete(`${APIURL}/contacts/${id}`);

These are functions are making our HTTP requests to the back end to save and delete contacts.

In HomePage.js , we put:

import React from 'react';
import { useState, useEffect } from 'react';
import Table from 'react-bootstrap/Table'
import ButtonToolbar from 'react-bootstrap/ButtonToolbar';
import Button from 'react-bootstrap/Button';
import Modal from 'react-bootstrap/Modal'
import ContactForm from './ContactForm';
import './HomePage.css';
import { connect } from 'react-redux';
import { getContacts, deleteContact } from './requests';

function HomePage() {
  const [openAddModal, setOpenAddModal] = useState(false);
  const [openEditModal, setOpenEditModal] = useState(false);
  const [initialized, setInitialized] = useState(false);
  const [selectedId, setSelectedId] = useState(0);
  const [selectedContact, setSelectedContact] = useState({});
  const [contacts, setContacts] = useState([]);
  const openModal = () => {
  const closeModal = () => {
  const cancelAddModal = () => {
  const editContact = (contact) => {
  const cancelEditModal = () => {
  const getData = async () => {
    const response = await getContacts();
  const deleteSelectedContact = async (id) => {
    await deleteContact(id);
  useEffect(() => {
    if (!initialized) {
  return (
    <div className="home-page">
      <Modal show={openAddModal} onHide={closeModal} >
        <Modal.Header closeButton>
          <Modal.Title>Add Contact</Modal.Title>
          <ContactForm edit={false} onSave={closeModal.bind(this)} onCancelAdd={cancelAddModal} />
<Modal show={openEditModal} onHide={closeModal}>
        <Modal.Header closeButton>
          <Modal.Title>Edit Contact</Modal.Title>
          <ContactForm edit={true} onSave={closeModal.bind(this)} contact={selectedContact} onCancelEdit={cancelEditModal} />
      <ButtonToolbar onClick={openModal}>
        <Button variant="outline-primary">Add Contact</Button>
      <br />
      <Table striped bordered hover>
            <th>First Name</th>
            <th>Last Name</th>
            <th>Postal Code</th>
          { => (
            <tr key={}>
                <Button variant="outline-primary" onClick={editContact.bind(this, c)}>Edit</Button>
                <Button variant="outline-primary" onClick={deleteSelectedContact.bind(this,}>Delete</Button>

const mapStateToProps = state => {
  return {
    contacts: state.contacts,

export default connect(

It has the table to display the contacts and buttons to add, edit, and delete contacts. It gets data on the first load with the getData function call in the useEffect’s callback function. useEffect’s callback is called on every render so we want to set a initialized flag and check that it loads only if it’s true .

Note that we pass in all the props in this component to the ContactForm component. To pass an argument a onClick handler function, we have to call bind on the function and pass in the argument for the function as a second argument to bind . For example, in this file, we have editContact.bind(this, c) , where c is the contact object. The editContact function is defined as follows:

const editContact = (contact) => {

c is the contact parameter we pass in.

In the styles block, we have:

.home-page {
  padding: 20px;

to add some padding.

In index.js in the pages folder, we replace the existing code with:

import React from "react";
import Head from "next/head";
import { Router, Route } from "react-router-dom";
import { createMemoryHistory as createHistory } from "history";
import Navbar from "react-bootstrap/Navbar";
import Nav from "react-bootstrap/Nav";
import HomePage from "./HomePage";
import { contactsReducer } from "../store/reducers";
import { Provider } from "react-redux";
import { createStore, combineReducers } from "redux";

const history = createHistory();

const addressBookApp = combineReducers({
  contacts: contactsReducer,

const store = createStore(addressBookApp);

const Home = () => (
      <title>Address Book</title>
    <div className="App">
      <Router history={history}>
        <Navbar bg="primary" expand="lg" variant="dark">
          <Navbar.Brand href="#home">Address Book App</Navbar.Brand>
          <Navbar.Toggle aria-controls="basic-navbar-nav" />
          <Navbar.Collapse id="basic-navbar-nav">
            <Nav className="mr-auto">
              <Nav.Link href="/">Home</Nav.Link>
        <Route path="/" exact component={HomePage} />
    <style jsx>{`
      .App {
        text-align: center;

export default Home;

This is the entry point of the app, we add the navigation menu here and also the route for the home page here. Since we do not have an index.html in a server side rendered app, we render the head tag of the page by putting the Head component here, along with the title and link components inside the Head . We include these to change the title and add the Bootstrap stylesheet respectively.

We have to add a file called _app.js in the pages folder to let us use our Redux store in all our components since this is not a normal client side rendered app. This file overrides the default App class in Next.js . The class is used for loading initialization code in our pages. There is no ReactDOM.render call with the topmost component where we can wrap the Provider component around it to let us use our Redux store everywhere, so we have to add:

// pages/_app.js
import React from "react";
import { Provider } from "react-redux";
import App, { Container } from "next/app";
import withRedux from "next-redux-wrapper";
import { contactsReducer } from "../store/reducers";
import { createStore, combineReducers } from "redux";

const addressBookApp = combineReducers({
  contacts: contactsReducer,

const makeStore = (initialState, options) => {
  return createStore(addressBookApp, initialState);

class MyApp extends App {
  static async getInitialProps({ Component, ctx }) {
    const pageProps = Component.getInitialProps
      ? await Component.getInitialProps(ctx)
      : {};
    return { pageProps };
  render() {
    const { Component, pageProps, store } = this.props;
    return (
        <Provider store={store}>
          <Component {...pageProps} />

export default withRedux(makeStore)(MyApp);

to wrap our Redux store around all our components. Component is any component in our app. We use the next-redux-wrapper package to pass the store object down to all of our components by allowing us to wrap Provider with the store prop around our components.

Now we can run the app by running npm run build then npm run start -- --port 3001 .

To start back end, we first install the json-server package by running npm i json-server . Them go to our project folder and run:

json-server --watch db.json

In db.json , change the text to:

  "contacts": [

so that we have the contacts endpoints defined in requests.js available.

At the end, we have the following:

Thank for visiting and reading this article! I’m highly appreciate your actions! Please share if you liked it!

#React #Nextjs #JavaScript #Programming #Webdev

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How to Create Server Side Rendered React application using Next.js
Autumn  Blick

Autumn Blick


How native is React Native? | React Native vs Native App Development

If you are undertaking a mobile app development for your start-up or enterprise, you are likely wondering whether to use React Native. As a popular development framework, React Native helps you to develop near-native mobile apps. However, you are probably also wondering how close you can get to a native app by using React Native. How native is React Native?

In the article, we discuss the similarities between native mobile development and development using React Native. We also touch upon where they differ and how to bridge the gaps. Read on.

A brief introduction to React Native

Let’s briefly set the context first. We will briefly touch upon what React Native is and how it differs from earlier hybrid frameworks.

React Native is a popular JavaScript framework that Facebook has created. You can use this open-source framework to code natively rendering Android and iOS mobile apps. You can use it to develop web apps too.

Facebook has developed React Native based on React, its JavaScript library. The first release of React Native came in March 2015. At the time of writing this article, the latest stable release of React Native is 0.62.0, and it was released in March 2020.

Although relatively new, React Native has acquired a high degree of popularity. The “Stack Overflow Developer Survey 2019” report identifies it as the 8th most loved framework. Facebook, Walmart, and Bloomberg are some of the top companies that use React Native.

The popularity of React Native comes from its advantages. Some of its advantages are as follows:

  • Performance: It delivers optimal performance.
  • Cross-platform development: You can develop both Android and iOS apps with it. The reuse of code expedites development and reduces costs.
  • UI design: React Native enables you to design simple and responsive UI for your mobile app.
  • 3rd party plugins: This framework supports 3rd party plugins.
  • Developer community: A vibrant community of developers support React Native.

Why React Native is fundamentally different from earlier hybrid frameworks

Are you wondering whether React Native is just another of those hybrid frameworks like Ionic or Cordova? It’s not! React Native is fundamentally different from these earlier hybrid frameworks.

React Native is very close to native. Consider the following aspects as described on the React Native website:

  • Access to many native platforms features: The primitives of React Native render to native platform UI. This means that your React Native app will use many native platform APIs as native apps would do.
  • Near-native user experience: React Native provides several native components, and these are platform agnostic.
  • The ease of accessing native APIs: React Native uses a declarative UI paradigm. This enables React Native to interact easily with native platform APIs since React Native wraps existing native code.

Due to these factors, React Native offers many more advantages compared to those earlier hybrid frameworks. We now review them.

#android app #frontend #ios app #mobile app development #benefits of react native #is react native good for mobile app development #native vs #pros and cons of react native #react mobile development #react native development #react native experience #react native framework #react native ios vs android #react native pros and cons #react native vs android #react native vs native #react native vs native performance #react vs native #why react native #why use react native

Eva  Murphy

Eva Murphy


Google analytics Setup with Next JS, React JS using Router Events - 14

In this video, we are going to implement Google Analytics to our Next JS application. Tracking page views of an application is very important.

Google analytics will allow us to track analytics information.

App link:

You can find me on:

#next js #js #react js #react #next #google analytics

sophia tondon

sophia tondon


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NBB: Ad-hoc CLJS Scripting on Node.js


Not babashka. Node.js babashka!?

Ad-hoc CLJS scripting on Node.js.


Experimental. Please report issues here.

Goals and features

Nbb's main goal is to make it easy to get started with ad hoc CLJS scripting on Node.js.

Additional goals and features are:

  • Fast startup without relying on a custom version of Node.js.
  • Small artifact (current size is around 1.2MB).
  • First class macros.
  • Support building small TUI apps using Reagent.
  • Complement babashka with libraries from the Node.js ecosystem.


Nbb requires Node.js v12 or newer.

How does this tool work?

CLJS code is evaluated through SCI, the same interpreter that powers babashka. Because SCI works with advanced compilation, the bundle size, especially when combined with other dependencies, is smaller than what you get with self-hosted CLJS. That makes startup faster. The trade-off is that execution is less performant and that only a subset of CLJS is available (e.g. no deftype, yet).


Install nbb from NPM:

$ npm install nbb -g

Omit -g for a local install.

Try out an expression:

$ nbb -e '(+ 1 2 3)'

And then install some other NPM libraries to use in the script. E.g.:

$ npm install csv-parse shelljs zx

Create a script which uses the NPM libraries:

(ns script
  (:require ["csv-parse/lib/sync$default" :as csv-parse]
            ["fs" :as fs]
            ["path" :as path]
            ["shelljs$default" :as sh]
            ["term-size$default" :as term-size]
            ["zx$default" :as zx]
            ["zx$fs" :as zxfs]
            [nbb.core :refer [*file*]]))

(prn (path/resolve "."))

(prn (term-size))

(println (count (str (fs/readFileSync *file*))))

(prn (sh/ls "."))

(prn (csv-parse "foo,bar"))

(prn (zxfs/existsSync *file*))

(zx/$ #js ["ls"])

Call the script:

$ nbb script.cljs
#js {:columns 216, :rows 47}
#js ["node_modules" "package-lock.json" "package.json" "script.cljs"]
#js [#js ["foo" "bar"]]
$ ls


Nbb has first class support for macros: you can define them right inside your .cljs file, like you are used to from JVM Clojure. Consider the plet macro to make working with promises more palatable:

(defmacro plet
  [bindings & body]
  (let [binding-pairs (reverse (partition 2 bindings))
        body (cons 'do body)]
    (reduce (fn [body [sym expr]]
              (let [expr (list '.resolve 'js/Promise expr)]
                (list '.then expr (list 'clojure.core/fn (vector sym)

Using this macro we can look async code more like sync code. Consider this puppeteer example:

(-> (.launch puppeteer)
      (.then (fn [browser]
               (-> (.newPage browser)
                   (.then (fn [page]
                            (-> (.goto page "")
                                (.then #(.screenshot page #js{:path "screenshot.png"}))
                                (.catch #(js/console.log %))
                                (.then #(.close browser)))))))))

Using plet this becomes:

(plet [browser (.launch puppeteer)
       page (.newPage browser)
       _ (.goto page "")
       _ (-> (.screenshot page #js{:path "screenshot.png"})
             (.catch #(js/console.log %)))]
      (.close browser))

See the puppeteer example for the full code.

Since v0.0.36, nbb includes promesa which is a library to deal with promises. The above plet macro is similar to promesa.core/let.

Startup time

$ time nbb -e '(+ 1 2 3)'
nbb -e '(+ 1 2 3)'   0.17s  user 0.02s system 109% cpu 0.168 total

The baseline startup time for a script is about 170ms seconds on my laptop. When invoked via npx this adds another 300ms or so, so for faster startup, either use a globally installed nbb or use $(npm bin)/nbb script.cljs to bypass npx.


NPM dependencies

Nbb does not depend on any NPM dependencies. All NPM libraries loaded by a script are resolved relative to that script. When using the Reagent module, React is resolved in the same way as any other NPM library.


To load .cljs files from local paths or dependencies, you can use the --classpath argument. The current dir is added to the classpath automatically. So if there is a file foo/bar.cljs relative to your current dir, then you can load it via (:require [ :as fb]). Note that nbb uses the same naming conventions for namespaces and directories as other Clojure tools: foo-bar in the namespace name becomes foo_bar in the directory name.

To load dependencies from the Clojure ecosystem, you can use the Clojure CLI or babashka to download them and produce a classpath:

$ classpath="$(clojure -A:nbb -Spath -Sdeps '{:aliases {:nbb {:replace-deps {com.github.seancorfield/honeysql {:git/tag "v2.0.0-rc5" :git/sha "01c3a55"}}}}}')"

and then feed it to the --classpath argument:

$ nbb --classpath "$classpath" -e "(require '[honey.sql :as sql]) (sql/format {:select :foo :from :bar :where [:= :baz 2]})"
["SELECT foo FROM bar WHERE baz = ?" 2]

Currently nbb only reads from directories, not jar files, so you are encouraged to use git libs. Support for .jar files will be added later.

Current file

The name of the file that is currently being executed is available via nbb.core/*file* or on the metadata of vars:

(ns foo
  (:require [nbb.core :refer [*file*]]))

(prn *file*) ;; "/private/tmp/foo.cljs"

(defn f [])
(prn (:file (meta #'f))) ;; "/private/tmp/foo.cljs"


Nbb includes reagent.core which will be lazily loaded when required. You can use this together with ink to create a TUI application:

$ npm install ink


(ns ink-demo
  (:require ["ink" :refer [render Text]]
            [reagent.core :as r]))

(defonce state (r/atom 0))

(doseq [n (range 1 11)]
  (js/setTimeout #(swap! state inc) (* n 500)))

(defn hello []
  [:> Text {:color "green"} "Hello, world! " @state])

(render (r/as-element [hello]))


Working with callbacks and promises can become tedious. Since nbb v0.0.36 the promesa.core namespace is included with the let and do! macros. An example:

(ns prom
  (:require [promesa.core :as p]))

(defn sleep [ms]
   (fn [resolve _]
     (js/setTimeout resolve ms))))

(defn do-stuff
   (println "Doing stuff which takes a while")
   (sleep 1000)

(p/let [a (do-stuff)
        b (inc a)
        c (do-stuff)
        d (+ b c)]
  (prn d))
$ nbb prom.cljs
Doing stuff which takes a while
Doing stuff which takes a while

Also see API docs.


Since nbb v0.0.75 applied-science/js-interop is available:

(ns example
  (:require [applied-science.js-interop :as j]))

(def o (j/lit {:a 1 :b 2 :c {:d 1}}))

(prn (j/select-keys o [:a :b])) ;; #js {:a 1, :b 2}
(prn (j/get-in o [:c :d])) ;; 1

Most of this library is supported in nbb, except the following:

  • destructuring using :syms
  • property access using .-x notation. In nbb, you must use keywords.

See the example of what is currently supported.


See the examples directory for small examples.

Also check out these projects built with nbb:


See API documentation.

Migrating to shadow-cljs

See this gist on how to convert an nbb script or project to shadow-cljs.



  • babashka >= 0.4.0
  • Clojure CLI >=
  • Node.js 16.5.0 (lower version may work, but this is the one I used to build)

To build:

  • Clone and cd into this repo
  • bb release

Run bb tasks for more project-related tasks.

Download Details:
Author: borkdude
Download Link: Download The Source Code
Official Website: 
License: EPL-1.0

#node #javascript

Mathew Rini


How to Select and Hire the Best React JS and React Native Developers?

Since March 2020 reached 556 million monthly downloads have increased, It shows that React JS has been steadily growing. React.js also provides a desirable amount of pliancy and efficiency for developing innovative solutions with interactive user interfaces. It’s no surprise that an increasing number of businesses are adopting this technology. How do you select and recruit React.js developers who will propel your project forward? How much does a React developer make? We’ll bring you here all the details you need.

What is React.js?

Facebook built and maintains React.js, an open-source JavaScript library for designing development tools. React.js is used to create single-page applications (SPAs) that can be used in conjunction with React Native to develop native cross-platform apps.

React vs React Native

  • React Native is a platform that uses a collection of mobile-specific components provided by the React kit, while React.js is a JavaScript-based library.
  • React.js and React Native have similar syntax and workflows, but their implementation is quite different.
  • React Native is designed to create native mobile apps that are distinct from those created in Objective-C or Java. React, on the other hand, can be used to develop web apps, hybrid and mobile & desktop applications.
  • React Native, in essence, takes the same conceptual UI cornerstones as standard iOS and Android apps and assembles them using React.js syntax to create a rich mobile experience.

What is the Average React Developer Salary?

In the United States, the average React developer salary is $94,205 a year, or $30-$48 per hour, This is one of the highest among JavaScript developers. The starting salary for junior React.js developers is $60,510 per year, rising to $112,480 for senior roles.

* React.js Developer Salary by Country

  • United States- $120,000
  • Canada - $110,000
  • United Kingdom - $71,820
  • The Netherlands $49,095
  • Spain - $35,423.00
  • France - $44,284
  • Ukraine - $28,990
  • India - $9,843
  • Sweden - $55,173
  • Singapore - $43,801

In context of software developer wage rates, the United States continues to lead. In high-tech cities like San Francisco and New York, average React developer salaries will hit $98K and $114per year, overall.

However, the need for React.js and React Native developer is outpacing local labour markets. As a result, many businesses have difficulty locating and recruiting them locally.

It’s no surprise that for US and European companies looking for professional and budget engineers, offshore regions like India are becoming especially interesting. This area has a large number of app development companies, a good rate with quality, and a good pool of React.js front-end developers.

As per Linkedin, the country’s IT industry employs over a million React specialists. Furthermore, for the same or less money than hiring a React.js programmer locally, you may recruit someone with much expertise and a broader technical stack.

How to Hire React.js Developers?

  • Conduct thorough candidate research, including portfolios and areas of expertise.
  • Before you sit down with your interviewing panel, do some homework.
  • Examine the final outcome and hire the ideal candidate.

Why is React.js Popular?

React is a very strong framework. React.js makes use of a powerful synchronization method known as Virtual DOM, which compares the current page architecture to the expected page architecture and updates the appropriate components as long as the user input.

React is scalable. it utilises a single language, For server-client side, and mobile platform.

React is steady.React.js is completely adaptable, which means it seldom, if ever, updates the user interface. This enables legacy projects to be updated to the most new edition of React.js without having to change the codebase or make a few small changes.

React is adaptable. It can be conveniently paired with various state administrators (e.g., Redux, Flux, Alt or Reflux) and can be used to implement a number of architectural patterns.

Is there a market for React.js programmers?
The need for React.js developers is rising at an unparalleled rate. React.js is currently used by over one million websites around the world. React is used by Fortune 400+ businesses and popular companies such as Facebook, Twitter, Glassdoor and Cloudflare.

Final thoughts:

As you’ve seen, locating and Hire React js Developer and Hire React Native developer is a difficult challenge. You will have less challenges selecting the correct fit for your projects if you identify growing offshore locations (e.g. India) and take into consideration the details above.

If you want to make this process easier, You can visit our website for more, or else to write a email, we’ll help you to finding top rated React.js and React Native developers easier and with strives to create this operation

#hire-react-js-developer #hire-react-native-developer #react #react-native #react-js #hire-react-js-programmer