Backend 5 Topics

ABU BAKKAR SIDDIQUE — Thu, 23 Dec 2021 15:47:30 +0000

CRUD Operations
CRUD means Create, Read, Update, Delete. Create is used to create posts in the Database. Read is used to Read posts in the Database. Update is used to update a post in the database. Delete method is used to delete a post from the database.

Mongoose
Mongoose is basically a package. Which serves as a mediator between the NodeJS application and MongoDB server. It is an Object Document Mapper(ODM) that allows us to define objects with strongly-typed-schema that are mapped to a MongoDB document. Mongoose supports all the CRUD operations – Creating, Retrieving, Updating, and Deleting.

JWT
JSON Web Token (JWT) is an open standard. Which defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed. JWTs can be signed using a secret key.

Although JWTs can be encrypted to also provide secrecy between parties, we will focus on signed tokens. Signed tokens can verify the integrity of the claims contained within it, while encrypted tokens hide those claims from other parties. When tokens are signed using public/private key pairs, the signature also certifies that only the party holding the private key is the one that signed it.

Express.js
Express.js is a back end web application framework for Node.js. It is released as free and open-source software under the MIT License. It is designed for building web applications and APIs. It has been called the de facto standard server framework for Node.js.
Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications.

Relational Database
A relational database is a collection of data items with pre-defined relationships between them. These items are organized as a set of tables with columns and rows. Tables are used to hold information about the objects to be represented in the database. Each column in a table holds a certain kind of data and a field stores the actual value of an attribute. The rows in the table represent a collection of related values of one object or entity. Each row in a table could be marked with a unique identifier called a primary key, and rows among multiple tables can be made related using foreign keys. This data can be accessed in many different ways without reorganizing the database tables themselves.

Some react.js topic

ABU BAKKAR SIDDIQUE — Wed, 22 Dec 2021 14:45:05 +0000

JSX(JavaScript XML)
Generally we know JSX means JavaScript XML.

const JSXDemo = () => {
    return (
     <h1>I am a React.js Developer</h1>
      )
}

Here are <h1>I am a React.js Developer</h1> this syntax is not HTML or not a string. This is called JSX. In JSX we can use dynamic. Developers can keep javascript expressions in JSX. JSX is also a javascript expression. After the compilation, JSX expressions are converted into a javascript function call and then catalyzed into a javascript object. In this JSX we can use the CSS attribute as a string for styling elements.

Context API
React context is a method which allows developers to pass data from component to component without using props.
Example:

import React from ‘react’;

export const UserContext = React.createContext();

const App = () => {
    return (
        <UserContext.Provider>
            <User></User>
        </UserContext.Provider>
)
}

Custom hooks in React
Developers can build their own hooks which are reusable functions. When we want to share logic between two JavaScript functions, we extract it to a third function. Both components and Hooks are functions, so this works for them too!
Example:
Create a custom hook:

const useRainyStatus = (rainy) => {
    const [isRaining, setIsRaining] = useState(null);

    return isRaining;
}

Let’s now use this custom hook:

const rainyStatus = (props) => {
    const isRaining = useRainyStatus(props.raining.yes);

if(isRaining === null) {
        return ‘just wait a sec..’;
}
return isRaining ? ‘Raining’ : ‘Not Raining’;
}

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Backend 5 Topics

Some react.js topic