Understanding and Implementing Schemas in Python

-
Understanding and Implementing Schemas in Python Introduction In the world of programming, particularly in the context of data management and validation, schemas play a vital role. A schema is essentially a blueprint or a predefined structure that defines the expected format, data types, and constraints for a given data entity. In this blog, we will delve into the concept of schemas in Python, exploring what they are, why they are important, and how you can implement them in your projects. What is a Schema? A schema serves as a contract between different components of a system, ensuring that data is consistent, valid, and well-structured. It defines the rules for how data should be organized, what fields it should contain, and what types of values those fields can hold. In essence, a schema acts as a set of rules that data must adhere to in order to be considered valid. Why Are Schemas Important? Data Validation: Schemas provide a way to validate incoming data. When data is received o
Post a Comment

Interview Question | React Js

-

Interview Question | React Js 

Recently, I had given one interview in React Js & one of the member from interview panel had given me following task to complete.

Task contains following requirements to complete:

a) Initially, show 7 rectangle boxes in white color & all should be clickable.

b) Once you click rectangle box, show that in green color.

c) As soon as, you click seventh rectangle box, make all rectangle boxes white again after some time interval in reverse order.

Sample Code:

A) App.js


import React, { useState, useEffect } from 'react';
import './style.css';

const rectangle = [
  { rectId: 1, rectColor: 'white' },
  { rectId: 2, rectColor: 'white' },
  { rectId: 3, rectColor: 'white' },
  { rectId: 4, rectColor: 'white' },
  { rectId: 5, rectColor: 'white' },
  { rectId: 6, rectColor: 'white' },
  { rectId: 7, rectColor: 'white' },
];

let count = 0;

export default function App() {
  
  const [showrectangle, setShowrectangle] = useState(rectangle);
  const [action, setAction] = useState(false);

  const onClickDiv = (id) => {
    const newArr = showrectangle.filter((item) => {
      if (item.rectId === id) {
        item.rectColor = 'green';
        return item;
      }
      return item;
    });
    setShowrectangle(newArr);

    if (id === 7) {
      setAction(true);
      count = 7;
    } else setAction(false);
  };

  useEffect(() => {
    if (action) {
      if (count !== 0) {
        const timeOut = setTimeout(() => {
          const arr = showrectangle.filter((item) => {
            if (item.rectId === count) {
              item.rectColor = 'white';
              return item;
            }
            return item;
          });
          setShowrectangle(arr);
          count--;
        }, 1500);

        return () => {
          clearTimeout(timeOut);
        };
      } else {
        setAction(false);
      }
    }
  }, [action, showrectangle]);

  return (
    <div>
      {showrectangle &&
        showrectangle.length > 0 &&
        showrectangle.map((item) => {
          return (
            <div
              style={{
                width: '25px',
                height: '20px',
                border: '1px solid black',
                float: 'left',
                margin: '12px',
                backgroundColor: item.rectColor,
              }}
              key={item.id}
              onClick={() => onClickDiv(item.rectId)}
            ></div>
          );
        })}
    </div>
  );
}


Happy Learning!! Happy Coding!!

Comments

New comments are not allowed.

Popular posts from this blog

useNavigate and useLocation hooks react-router-dom-v6

-
Image
useNavigate and useLocation hooks - Navigating programmatically to a route. In this post, we will learn about two new hooks from react-router-dom version 6 library. 1) useNavigate - Let’s say on click of a button, If you want to perform redirection to the page, then react router provide us with a hook called as useNavigate. - useNavigate hook replaced useHistory hook, but it works same as useHistory but in addition it has good feature. - useNavigate hook is only available in react-router-dom version 6. - We can redirect to Previous and Next page with the help of useNavigate hooks.  2) useLocation - We required two library React 16.8+ and react-router-dom 5.1+ for useLocation hook. - It is a function that returns the location object that contains information about the current URL. - New location object is created, whenever the URL changed. useNavigate and useLocation hooks react router dom version 6Js and Xstate Install React Router Command npm install react-router-dom --save Sample cod
Read more

How to implement error boundaries in React Js

-
Error boundaries in React Js In this post, we will learn about "Error Boundaries in React Js". First of all, why we required Error Boundaries? This is the first question comes in my mind, as before React 16, we don't have any mechanism to catch error inside components and because of which whole app in broken state on next renders. No ways to handle these errors in React Components, nor it gives any methods to recover from them. React 16 introduces a new concept to handle such errors by using the error boundaries. So now, if any error found in a part of the UI, it does not break the whole application. According to official document of React Js, There are following few areas in application, where error boundaries are not suitable solution. a) Event handlers b) Asynchronous code (e.g., setTimeout) c) Server-side rendering d) Errors are thrown in the error boundary itself  For complex application which contains multiple components, we can declare multiple error boundaries to
Read more

Pass data from child component to its parent component in React Js

-
Image
Pass data from child component to its parent component in React Js In this post, we will learn about how to pass data from child component to its parent component in React js. We need to do following steps to pass/send data from child component to parent component: a) In the parent component, create a callback function. This callback function is useful to retrieve the data from the child component. b) Pass the callback function to the child as a props from the parent component. c) The child component calls the parent callback function using props and sends the data to the parent component. Send data from child component to its parent component Sample Code: A) index.js import   React   from   "react" ; import   ReactDOM   from   "react-dom" ; import   App   from   "./App" ; ReactDOM . render ( < App   /> ,  document . getElementById ( "root" )); B) App.js import   React , {  useState  }  from   'react' ; import   './style.css'
Read more

Localization in React Js

-
Image
Localization in React Js using react-localization package. In this post, we will learn about Localization in React Js. Now a day, Localization is very important and basic requirement in every web based application. Following source code will help you, creating a multilingual Web application in React Js. Note: Use Double Click for Radio Boxes. Localization in React Js Installation: npm install --save react-localization Folder Structure: Sample Code A) index.js import   React   from   "react" ; import   ReactDOM   from   "react-dom" ; import   App   from   "./App" ; ReactDOM . render ( < App   /> ,  document . getElementById ( "root" )); B) App.js ( Class Component ) import   React , {  Component  }  from   'react' ; import   labels   from   './Local/localize' ; import   './style.css' ; class   App   extends   Component  {    constructor ( props ) {      super ( props );      this . state  = {        language:   '
Read more

Create a Shopping Item App using React Js and Xstate

-
Image
Create a Shopping Item App using React Js and Xstate ( state management )  In this post, we will create a shopping item app using React js and Xstate. Generally, we use redux for state management but in this application, I am going to show you state management with the help of Xstate. Shopping Item App using React Js and Xstate Dependency:   npm install xstate @xstate/react Folder Structure: Sample Code: A) index.js import   React   from   "react" ; import   ReactDOM   from   "react-dom" ; import   App   from   "./App" ; ReactDOM . render ( < App   /> ,  document . getElementById ( "root" )); B) App.js import   React   from   'react' ; import   Product   from   './Product/Product' ; import   './style.css' ; import  { ShoppingContext ,  ShoppingMachine }  from   './State/index' import  {  useMachine  }  from   '@xstate/react' ; export   default   function   App () {    const  [ currentStates ,  sendToM
Read more

How to fetch data from an API using fetch() method in React Js

-
Image
How to fetch data from an API using fetch() method in React Js? Now a day, we can't imagine web application without API so one of the basic requirement of any web application is to communicate with servers through HTTP protocol. This can be easily done using Fetch and Axios .  In this post, we are mainly focusing on Fetch. The Fetch API provides a fetch() method defined on the window object. The fetch method has one mandatory argument i.e., URL of the resource to be fetched. This method returns promise object that can be used to retrieve response of the request.  There are following limitations of Fetch API: a) Fetch does not allows cancelling request and request timeout. b) Fetch does not provide a way to intercept HTTP requests. c) Fetch has no url in request object. d) No installation is required. e) Fetch does not have XSRF protection. f) Fetch uses the body property. g) Fetch is a two step process when handling JSON data, first - to make actual request. second - to call json()
Read more

How to fetch data using Axios Http Get Request in React Js?

-
Image
How to fetch data using  Axios - Http Get Request in React Js? In one of my previous post, I had explained all about Fetch() method to retrieve data from api server. In this post, I am going to demystify how to achieve same thing using axios. Axios has many advantages over fetch() method. 1) Axios has the ability to intercept HTTP request. 2) With axios.all() method, you can make simultaneous requests, simply send an array of request to this method, then use axios.spread() method to assign the properties of the response array to separate varialbes. 3) Axios automatically stringifies the data when sending requests, as in fetch() method, you would have to do it manually. 4) You can set response timeout. 5) Support backward compatibility, this is because it uses XMLhttprequest under the hood.  Fetch User Data Using Axios - Get Request Installation: npm install axios or yarn add axios Sample Code: A) index.js import   React   from   "react" ; import   ReactDOM   from   "rea
Read more

Routing in React using React-Router Version 6

-
Image
 Routing in React using React-Router Version 6 What is Routing? - The process of navigating a user to different pages based on their request is known as routing. - Routing is a process of binding a web URL to specific resource. In react we can say, "it is a binding of URL to a specific component. - As react is a user interface library, it does not support routing. - In this post, we will learn about "routing in react using  react-router-dom  library version 6". Install React Router Command npm install react-router-dom --save Main component used for Navigation 1) BrowserRouter as Router - top level component  2) Routes - Replacement of Switch component. 3) Route - child component of Routes, useful for mapping a specific URL to a component. 4) Link - Similar to anchor tag in html. Note:  Switch Component is deprecated from version 6. The new component is introduced called as  Routes . Multiple Routing in React Js Installation:  npm install react-router-dom --save Sample Co
Read more

Create a custom calendar in React Js | Interview Question

-
Image
Create a custom calendar in React Js ( React Hooks ) | Interview Question In this post, you will learn about "how to create a custom calendar with the help of React Js". This is very simple calendar component in which you will be able to select a date from active month. Once you understand this component, you can add more functionalities to this as per your need. I am assuming that you have basic understanding of React, html & css. Calendar in React Js Sample Code: A) App.js import   React , {  useState ,  useEffect  }  from   'react' ; import   './style.css' ; export   default   function   App () {    const  [ daySel ,  setDaySel ] =  useState ( new   Date ());    const  [ currentMonth ,  setCurrentMonth ] =  useState ([]);    const  [ month ,  setMonth ] =  useState ( new   Date (). getMonth ());    const  [ year ,  setYear ] =  useState ( new   Date (). getFullYear ());    const   days  = [     {  id:   0 ,  day:   'SUN'  },     {  id:   1 ,  da
Read more

Environment Setup and Installation for React Js Application

-
Image
Environment Setup and Installation for React Js Application In this post, you will learn about “how to set up an environment for React Application”. There are many steps involved, in which first and important step is to install Node Js and npm.                Install Node Js -  Node Js is an open-source, cross-platform, back-end JavaScript runtime environment that runs on the V8 engine. - After invention of Node Js, we are able to execute JavaScript code outside a web browser. - NPM will be installed along with Node Js. - Node Js can be downloaded and installed from official Node Js website: https://nodejs.org/en/ -         After successful installation of Node Js, Open Command Prompt in order to check its version as shown in below. Install Create-React-App -         Second step is to install a tool called Create-React-App using NPM which will be useful for creating react application easily from our system. -         You can install this at the system level or global level. -         W
Read more