DEV Community: Manoj Kumar

Most Asked JavaScript Interview Questions & Answers

Manoj Kumar — Sun, 04 Feb 2024 15:11:43 +0000

1. What is JavaScript, and how does it differ from Java?
JavaScript is a lightweight, interpreted programming language primarily used for web development. Unlike Java, which is a full-fledged, object-oriented programming language, JavaScript is a scripting language embedded within HTML pages to enhance interactivity.

2. Explain the concept of closures in JavaScript.
Closures occur when a function retains access to variables from its outer scope, even after the outer function has finished executing. This allows for the creation of private variables and encapsulation of functionality.

function outerFunction() {
  let outerVariable = 10;

  function innerFunction() {
    console.log(outerVariable);
  }

  return innerFunction;
}

const closureExample = outerFunction();
closureExample(); // Outputs: 10

3. What is the event loop in JavaScript?
The event loop manages the execution of code, handling events and executing callbacks. It consists of a message queue, an event loop, and a callback or “message handler.”

4. Describe the differences between let, const, and var.
var is function-scoped and hoisted.
let and const are block-scoped, and const does not allow reassignment.

function example() {
  if (true) {
    var x = 5; // Function-scoped
    let y = 10; // Block-scoped
    const z = 15; // Block-scoped and cannot be reassigned
  }

  console.log(x); // Outputs: 5
  console.log(y); // Error: y is not defined
  console.log(z); // Error: z is not defined
}

5. How does prototypal inheritance work in JavaScript?
JavaScript uses prototypal inheritance, where objects can inherit properties and methods from other objects. Each object has a prototype chain, and if a property or method is not found in the object, JavaScript looks up the chain until it finds it.

function Animal(name) {
  this.name = name;
}

Animal.prototype.sound = function () {
  console.log("Some generic sound");
};

function Dog(name, breed) {
  Animal.call(this, name);
  this.breed = breed;
}

Dog.prototype = Object.create(Animal.prototype);
Dog.prototype.constructor = Dog;

Dog.prototype.sound = function () {
  console.log("Bark!");
};

const myDog = new Dog("Buddy", "Labrador");
myDog.sound(); // Outputs: Bark!```

20 Most Asked JavaScript Interview Questions & Answers

I Created Responsive Blog Website Using React, NodeJS, and MongoDB

Manoj Kumar — Fri, 04 Jun 2021 10:05:16 +0000

I written many blog on different Website. But now I created a Blog Website using React, NodeJS, and MongoDB.

I created Frontend of Website using React, Created API using NodeJS, and used MongoDB Atlas for storing blog data and Articles.

In this website the is functionality to filter articles using tag name.

Live Demo

I Deployed it on Heroku.

How is the Website?
And
Please Let me Know if any change I need to do.

I Created a Responsive Portfolio Website Using HTML, CSS, Bootstrap, and JavaScript-Updated

Manoj Kumar — Wed, 25 Nov 2020 09:29:02 +0000

I already had created my portfolio from scratch using HTML, CSS, Bootstrap, and javascript. But this time I have updated my portfolio with attractive and responsive UI.

Tell me, what amazes you? What should I change?

Here is the link to the portfolio:http://manojcse.me

Your feedback will be very important to me. It will help to enhance my development skill.

If you liked the style of the button and want to use it, then visit here :MJBUTTON

If you don't know web technology or don't have time to create your portfolio from scratch. No Problem! I have created a tool for you it will create your portfolio with in 5 minutes without any coding. Try It

How To Become A Microsoft Learn Student Ambassador

Manoj Kumar — Wed, 28 Oct 2020 18:56:13 +0000

Video Link

Activate Azure for Students using GitHub Student Developer Pack.

Manoj Kumar — Wed, 28 Oct 2020 18:43:22 +0000

As a student, you can apply for the GitHub Student Developer Pack, which includes offers and benefits from GitHub partners. You can use the GitHub student developer pack to activate your Microsoft Azure account so that you can access the benefits.

How to apply for the GitHub Student Developer Pack

Visit here to get step by step instruction to apply for Github Student Developer Pack. : -How to apply for the GitHub Student Developer Pack

How to activate Azure from your pack

Once you get the confirmation email for your student developer pack. you need to go back to the Github website using this link Offers and avail the benefits.

There will be many tools available so you need to scroll down and find Microsoft Azure. Click to generate your unique code.

Click on Get access by connecting your GitHub account on Microsoft Azure

Now go to the Microsoft website and click on the “Activate Now” button where you’ll get a prompt to sign in. And sign in with your existing Microsoft account or sign in with GitHub.

Enter your details and you’ll see a page like this:

Click on the dropdown icon and select the Verification code. Copy your verification code from your Git website and paste it here.

You can now access your Azure account.

If you have not Verification code, Then go to contact and write your issue.

Sample:
Hi Microsoft
I’m a Github student developer pack member, and I’m trying to activate my azure account but I have not received any verification code. Please provide me the Verification Code.

You will get a mail from Microsoft Support

Reply to this mail with the required details then you will get the activation code.

If You have any doubt feel free to contact me.

Twitter

Linkdin

How to apply for the GitHub Student Developer Pack.

Manoj Kumar — Wed, 28 Oct 2020 18:24:25 +0000

You can get ahead in your career and access the best developer tools used in the industry, for free, with the GitHub Student Developer Pack (the Pack). The Pack is open to every student 13 years or older in a degree-granting program, and they are committed to helping every student — no matter where you are.

Most students apply for the Pack using their school-issued email address. However, students whose schools don’t provide email addresses are able to apply for the Pack using their dated student ID.

How to apply for the GitHub Student Developer Pack

Visit GitHub Education and click Get benefits in the top-right corner.

Then click on Get Pack

And login with Your Git hub Account

Under “Which best describes your academic status?”, select Student.

Then, complete one of the following:

If you have a school-issued email, select (or add it).

If you don’t have a school-issued email, follow the prompts to fill out additional information. You’re still eligible even if you only have a personal Gmail address, as long as you can provide alternative documentation to verify your current student status.

The next step is to add your college name.

The last step is to describe the purpose of how do you plan to use Github.

Verify your application details, and click on “Submit your Information”.

Approximately two weeks after submission of the application.

Common Questions

1. My school does not provide student emails or IDs. What can I submit to prove that I’m a student?

GitHub will consider any documentation you provide. If they cannot accept your uploaded proof on your first attempt, you will receive an email asking you to submit supplementary information.

2. My application wasn’t accepted. What should I do?

You may need to provide additional documentation before they can approve your application. A common problem is that the uploaded proof was undated, or the photo was too blurry. Regardless of the reason, they will try to provide context so that your next application has a greater chance of success.

What I Learned From Hacktoberfest

Manoj Kumar — Sat, 17 Oct 2020 15:34:39 +0000

What I Learned From Hacktoberfest

It was a great experience for me as a student. I explored many skills such intro to open source, etc.
Overall it was a great experience for me.. Thanks DigitalOcean Hacktoberfest Community

Portfolio Website Builder - Build Your Portfolio Within 10 minutes Without Coding

Manoj Kumar — Sat, 29 Aug 2020 21:22:02 +0000

You need a resume that you can update and share at any given moment. On top of that, potential employers should also be able to find you online with a quick search of your name. Having a well-designed CV website that conveys your personality sends a clear message to recruiters that you are serious about your career.

Why You Should Create a Personal Website ASAP

A personal website helps recruiters find you much more easily.
By having a personal website, you'll gain a competitive advantage.
A personal website gives you the freedom to be creative.
Having a personal website helps you acquire new skills.
Having a personal website will boost your chances of landing a job

So I came up with an amazing tool to make this an easy experience.
Resume Website Builder tool provides a beautiful UI to create a Resume website (Portfolio) in an easy and efficient way.

Just fill some details like Name, About, Education, Experiences, Skills, etc With a Simple and attractive UI.
Click on the submit button to create your resume Website.
Click on Show/Hide Code Button and copy your website code by
clicking on Click to copy button

🚀Try it out:Live Demo

How it Works Watch Video

Currently It has only one theme but I'm working hard I will come with new multiple themes ASAP.

If you like the tool, show some love by leaving a star on the GitHub repository.

Deploy a machine learning model using flask

Manoj Kumar — Fri, 21 Aug 2020 16:57:25 +0000

As a beginner in machine learning, it might be easy for anyone to get enough resources about all the algorithms for machine learning and deep learning but when I started to look for references to deploy ML model to production I did not find really any good resources which could help me to deploy my model as I am very new to this field. So, when I succeeded to deploy my model using Flask on Heroku, I decided to write an article to help others to simply deploy their model. I hope it will help:)

Live Demo
In this article, we are going to use simple logistic regression algorithm with scikit-learn for simplicity, we will use Flask as it is a very light web framework. We will create two files,

model.py
app.py

In a model.py file, we will develop and train our model, in an app.py, we will code to handle POST requests and return the results.

model.py

In this file, we will develop our ML model and train it. We will predict the heart disease of a person on the Basis of Symptoms. You can find the dataset here.

import pandas as pd
import sys
import numpy as np
import pickle
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LogisticRegression

Importing the libraries that we are going to use to develop our model. NumPy and pandas to manipulate the matrices and data respectively, sklearn.model_selection for splitting data into train and test set and sklearn.linear_model to train our model using LogisticRegression. pickle to save our trained model to the disk.

df=pd.read_csv('heart-data.csv')
x=df.drop('target', axis=1)
y=df['target']

We have imported the dataset using pandas and separated the features and label from the dataset.

train_x,valid_x,train_y,valid_y=train_test_split(x,y,test_size=0.3,random_state=35)

In this section, we have split our data into train and test size of 0.70 and 0.30 respectively using train_test_split from sklearn.

logr=LogisticRegression()
logr.fit(train_x,train_y)
result=logr.predict(valid_x)

The object is instantiated as a logr of the class LogisticRegression() and trained using tarin_x and train_y. Latter the predicted results are stored in the result.

pickle.dump(logr,open('model.pkl','wb'))
model=pickle.load(open('model.pkl','rb'))

We will save our trained model to the disk using the pickle library. Pickle is used to serializing and de-serializing a Python object structure. In which python object is converted into the byte stream.

In our case, we want to save our model so that it can be used by the server. So we will save our object logr to the file named model.pkl.

Here, our model.py is ready to train and save the model. The whole code of model.py is as follows.

# Importing the libraries
import pandas as pd
import sys
import numpy as np
import pickle
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LogisticRegression

# Importing the dataset
df=pd.read_csv('heart-data.csv')
df.rename(columns={"class":"target"},inplace=True)
df['target'].replace(['absent','present'],[0,1],inplace=True)
df=pd.get_dummies(df)
x=df.drop('target', axis=1)
y=df['target']
#Splitting the dataset into the Training set and Test set
train_x,valid_x,train_y,valid_y=train_test_split(x,y,test_size=0.3,random_state=35)

# Fitting Simple Linear Regression to the Training set
logr=LogisticRegression()
logr.fit(train_x,train_y)
pickle.dump(logr,open('model.pkl','wb'))
model=pickle.load(open('model.pkl','rb'))

# Predicting the Test set results
result=model.predict(valid_x)
print(result)

2.app.py

In this file, we will use the flask web framework to handle the POST requests that we will get from the UX.

Importing the methods and libraries that we are going to use in the code.

from flask import Flask
from flask import render_template,redirect,request
import pandas as pd
import sys
import numpy as np
import pickle

In the following section of the code, we have created the instance of the Flask() and loaded the model into the model.

app=Flask(__name__)

model=pickle.load(open('model.pkl','rb'))

Here, we have a method result(). In which resut method gets the data from the form passed by the users. model.predict() method takes input from the form and converts it into 2D numpy array the results are stored into the variable named result and we return this variable.

@app.route("/result", methods = ['POST', 'GET'])
def result():
    if request.method=='POST':
#geting data from html form
        age=request.form["age"]
        .
        .
# after geting data appending in a list
        lst=list()
        lst.append((age))
        lst.append((sex))
        lst.append((chest))
        lst.append((resting_blood_pressure))
        lst.append((serum_cholestoral))
        lst.append((fasting_blood_sugar))
        lst.append((resting_electrocardiographic_results))
        lst.append((maximum_heart_rate_achieved))
        lst.append((exercise_induced_angina))
        lst.append((oldpeak))
        lst.append((slope))
        lst.append((number_of_major_vessels))
        lst.append((thal))
# converting list into 2 D numpy array
        ans=model.predict([np.array(lst,dtype='int64')])
        result=ans[0]
        return render_template("result.html",result=result)

    else:
        return render_template("index.html")

Finally, we will run our app by the following code section. Here I have used port 5000 and have set debug=True since if we get any error we can debug it and solve it.


if __name__=='__main__':
    app.run(port=5000,debug=True)

You can find all the coding in my Github repository, heart-disease-predictor.
Don’t hesitate to flow your ideas in the comment section below.

Thank you :)

I Created a Responsive Portfolio Website Using HTML, CSS, Bootstrap, and JavaScript

Manoj Kumar — Fri, 03 Jul 2020 22:30:43 +0000

I already had a portfolio but it was created by others. But now have created my portfolio from scratch using HTML, CSS, Bootstrap, and JavaScript.

Tell me, what amazes you? What should I change?

Here is the link to the portfolio:https://mjmaurya.github.io
OR
https://manojcse.netlify.app

Your feedback will be very important to me. It will help to enhance my development skill.

How to install Flutter, Configure with Android Studio, and Create a Simple App.

Manoj Kumar — Wed, 20 May 2020 08:54:00 +0000

System requirements

To install and run Flutter, your development environment must meet these minimum requirements:
Operating System: Windows 7 SP1 or later (64-bit)
Disk Space: 400 Mb (Except disk space of IDE/tools)
Tools: Flutter depends on these tools being available in your environment.
Windows PowerShell
Git for Windows

Get the Flutter SDK

Step 1- Go to URL https://flutter.dev/docs/get-started/install/windows and download the latest Flutter SDK.
Step 2- Unzip the zip file and place the contained flutter in the installation location for the Flutter SDK (For example, C:/src/flutter; do not install FLutter in a directory like C:/Program Files/ that requires relevant privileges).
Step 3- Update your path
From the Start search bar, enter ‘env’ and select “Edit environment variables for your account”.
Under User variable check an entry called Path.
Under Path click on the new tab and append the full path to flutter/bin. (Your full path should be like C:/src/flutter/bin).

Android Setup

Install Android Studio

Download and install Android Studio.
Start Android Studio, and go through the ‘Android Studio Setup Wizard’. This installs the latest Android SDK, Android SDK Command-line Tools, and Android SDK Build-Tools, which are required by Flutter when developing for Android.

Install the Flutter and Dart plugins

Open Android Studio.
Click Configure>Plugins.
Select the Fluter plugin and click install.
Click yes when prompted to install the Dart plugin.
Restart Android Studio.

Create a Hello World app

Open Android Studio.
Select Start a new Flutter project.
Select the Flutter application and click next.
Enter Project name
Setup Flutter SDK path and Project location.
Click next.
Enter your Company Domain(com.example.helloapp) and click finish.
Run applications on your phone or emulator.

DEV Community: Manoj Kumar

Most Asked JavaScript Interview Questions & Answers

20 Most Asked JavaScript Interview Questions & Answers

I Created Responsive Blog Website Using React, NodeJS, and MongoDB

I Created a Responsive Portfolio Website Using HTML, CSS, Bootstrap, and JavaScript-Updated

How To Become A Microsoft Learn Student Ambassador

Activate Azure for Students using GitHub Student Developer Pack.

How to apply for the GitHub Student Developer Pack

How to activate Azure from your pack

How to apply for the GitHub Student Developer Pack.

How to apply for the GitHub Student Developer Pack

Common Questions

1. My school does not provide student emails or IDs. What can I submit to prove that I’m a student?

2. My application wasn’t accepted. What should I do?

What I Learned From Hacktoberfest

What I Learned From Hacktoberfest

Portfolio Website Builder - Build Your Portfolio Within 10 minutes Without Coding

Why You Should Create a Personal Website ASAP

If you like the tool, show some love by leaving a star on the GitHub repository.

Deploy a machine learning model using flask

I Created a Responsive Portfolio Website Using HTML, CSS, Bootstrap, and JavaScript

How to install Flutter, Configure with Android Studio, and Create a Simple App.

System requirements

Get the Flutter SDK

Android Setup

Install Android Studio

Install the Flutter and Dart plugins

Create a Hello World app

Thank You, I hope it will help You.