spawn EPERM at ChildProcess.spawn (internal/child_process.js:407:11) at Object.spawn (child_process.js:553:9)

How to clear spawn EPERM at childProcess.spawn error in angular.

Find the import statement in your whole project “ctrl + shift + F” in your terminal and search.

import { $ } from ‘protractor’;

If you find the above import protractor in your angular project, the child process of angular gets an error. Because you using “$” for jquery.

import { $ } from ‘protractor’ => it is used for end to end testing for angular application. so both get a conflict in your application. Remove the above code and instead add

Declare var $:any;

Remove this line => import { $ } from ‘protractor’;
Add this line => Declare var $:any;
Then run the project.


If there is no protractor in your project. All code is fine then,
Go to System Configuration in your windows

System configuration => General

Set to the normal setup and go to services

System Configuration => Services

Enable all services and click on Apply. It will prompt you to restart your computer. Just restart and check the now the error came. If issue clear comment below. Sharing the knowledge is the best thing! Thanks for reading.

Wanna download some paid Udemy courses “fully free”.

Download Udemy Courses free

Udemy paid courses free torrent link download

All Latest 2020 & 2021 UDEMY courses of current web and hybrid web technology. All torrent links are compressed in 7zip. Please extract and download the videos in torrent. Each course are 100% worth valuable. Each courses are done by highest rankers like => Academind, Stephane Maarek and etc…

The download links are available for the courses like flutter, angular, Dart, Git and JavaScript.

Udemy videos free download

Angular – The Complete Guide (2020 Edition)

Download .Torrent file

Angular 7 Security Masterclass (with FREE E-Book)

Download .Torrent file

Build Responsive Real World Websites with HTML5 and CSS3

Download .Torrent file

Dart 2 Complete Bootcamp – Go Hero from Zero in Dart Flutter

Download .Torrent file

Dart and Flutter The Complete Developer’s Guide

Download .Torrent file

Flutter & Dart – The Complete Flutter App Development Course

Download .Torrent file

Flutter & Dart – The Complete Guide [2020 Edition]

Download .Torrent file

Flutter – Advanced Course

Download .Torrent file

Flutter – Beginners Course

Download .Torrent file

Git from Basics to Advanced Practical Guide for Developers

Download .Torrent file

JavaScript Understanding the Weird Parts

Download .Torrent file

Modern JavaScript From The Beginning

Download .Torrent file

The Complete Angular Course Beginner to Advanced

Download .Torrent file

Dream11 team creation logic and condition

Dream11 is one of the popular online betting games. Many of them are analyzing the team in different ways. For analyzing purposes there is a tool to generate a team according to credits and points.

How to create a team in dream 11?

Find the possibility of a combination that can able to make.

For example:
1) Wicket-keeper (1), Batsman (4), All Rounder(3), Bowler (3)
2) Wicket-keeper (2), Batsman (3), All Rounder(2), Bowler (4)
3) Wicket-keeper (1), Batsman (3), All Rounder(2), Bowler (5), and so on…

There are very few combinations there. you can easily able to find the combination according to the rule
wk (1-4), bat(3-6), all(1-4), bow(3-6) => Total 100 credits

So you know the combination and generate the team with removed unplayed players.

When you generate a team. The number of possibilities is high even though removes the unplayed players. Because the team generates not only 100 credits and less than 100 credits. Most of the games are not able to generate apt 100 credit.

Condition logic to generate Ipl team

Team1 = KXIP
Team2 = MI
Number of Players in a team = 11
Each player points and credits are different

step1: Split the WK(wicketkeeper) according to the Teams and stored in an array.
Team1 wk => 3 person
Team2 wk => 4 person

step2: If the user picks the combination [2(wk), 3(bat), 2(all), 5(bowl) ]
From above wicket keeper is 2
1)To generate possibilities of wk 2
1 wk from team1 with the highest point or credits
1 wk from team2 with the highest point or credits

2)To generate possibilities of batsman 3
Pick the highest 1 from team1 + Pick the highest 2 from team2
Pick the highest 2 from team1 + Pick the highest 1 from team2

3) To generate possibilities of allrounder 2
same as WK

4) To generate possibilities of bowler 5
Pick the highest 2 from team1 + Pick the highest 3 from team2 = 5 person
Pick the highest 3 form team 1 + Pick the highest 2 from team2 = 5 person
Pick the highest 1 from team 1 + Picket the highest 4 from team2 = 5 person
Pick the highest 4 from team 1 + Picket the highest 1 from team2 = 5 person

So totally,
WK has a combination of 2
Bat has a combination of 2
All-rounder has a combination of 2
Bowler has a combination of 4

The team generate with loop according to the separate combinations
1st loop => WK[0]+ Bat[0] + All[0] + Bowler[0] => check the credit below or equal to 100.
2nd loop => WK[0]+ Bat[0] + All[0] + Bowler[1]
3rd loop => WK[0]+ Bat[0] + All[0] + Bowler[2]
4th loop => WK[0]+ Bat[0] + All[0] + Bowler[3]
5th loop => WK[0]+ Bat[0] + All[0] + Bowler[4]
6th loop => WK[0]+ Bat[0] + All[1] + Bowler[0]
7th loop => WK[0]+ Bat[0] + All[1] + Bowler[1]
8th loop => WK[0]+ Bat[0] + All[1] + Bowler[2]
9th loop => WK[0]+ Bat[0] + All[1] + Bowler[3]
10th loop => WK[0]+ Bat[0] + All[0] + Bowler[0]
11th loop => WK[0]+ Bat[1] + All[0] + Bowler[1]
12th loop => WK[0]+ Bat[1] + All[0] + Bowler[2]
13th loop => WK[0]+ Bat[1] + All[0] + Bowler[3]
14th loop => WK[0]+ Bat[1] + All[1] + Bowler[0] …
and the loops going on find the groups which credits total equal to or lessthan 100.
Push the group into another array.

Team generation Tool

One of the most popular analyzing for IPL dream11 team generation is available here.

Python Strings | tutorial 4

How to add single quotes, double quotes, or both quotes in the python strings?


course = "Python's for everyone"
new_course = 'Python for "EveryOne"'
email = '''
Hi John!,

Welcome to helperscript to learn Python's for "Everyone"

Thank you,
Support Team
The output of String declaration – python 3

Triple quotes (”’Python for “Everyone””’) – Three single quotes from the start and three single quotes from the end. This type of string escapes all the symbols in the string.

Split string into an array (or) Split the string in python

Python string starts index with zero(0).

Example: course variable has string “Python for Everyone”

Course = ‘Python for Everyone’

Get the first character of a string in python


Get the second character of a string in python


Get the last character of a string in python


Get the last second character of a string in python


Get the first three character of a string in python


Remove the first character and remove the last 3 characters of a string in python


Remove the character after 6 index


Remove the first 6 characters in the string


Clone or copy the string



# strings
course = 'Python for Everyone'
print('course[0] = ' + course[0])
print('course[1] = ' + course[1])
print('course[-1] = ' + course[-1])
print('course[-2] = ' + course[-2])
print('course[0:3] = ' + course[0:3])
print('course[1:-3] = ' + course[1:-3])
print('course[:5] = ' + course[:6])
print('course[6:] = ' + course[6:])
print('course[:] = ' + course[:])


String Concatenation

Two ways to concat the string dynamically.

Normal way – firstname +’ ’+ lastname +’ is a coder’
Format way – f‘{firstname} {lastname} is a code’

f – prefix with f define a formatted string


string concatenation in python

Python strings method

course = ‘Python for Beginners’

# find the length of string

# convert uppercase

# convert lowercase

# convert first character uppercase in each word

# find an index of character or sequence of character.

 Python find() method is case sensitive.

print(course.find(‘P’))  # gives index of capital P
print(course.find(‘p’))  # return -1 if not present. 

# Replace a character
course.replace(‘P’, ‘J’)

# Replace a sequence of character
course.replace(‘Python’, ‘Angular’)

# find a string contains in the existing string(case sensitive)
‘Python’ in course

course = 'Python for Beginners'
# find the length of string
# convert uppercase
# convert lowercase
# convert first character uppercase in each word
# find index of character or sequence of character
print(course.find('P'))  # capital
print(course.find('p'))  # small letter
# Replace a character
print(course.replace('P', 'J'))
# Replace a sequence of character
print(course.replace('Python', 'Angular'))
# find a string contains in existing string
print('Python' in course) # gives boolean output either True or False
String Methods in python 3

In Next article, we see about Operators in Python.

PYTHON variables | tutorial 3

Python is a case sensitive language. So when you define a variable you should consider the uppercase and lowercase.

eg: price = 10 is different to PRICE = 10

Important Variable Types and Declaration

price = 10
# price variable type is INTEGER
# price is an identifier for variable and initialised with the value 10

update_price = 20.5
# update_price variable type is FLOAT

is_published = True
# is_published variable type is BOOLEAN
# either True or False (case sensitive first letter should be capital)

name = 'Jasim'
# name variable type is STRING

# – is a comment line. Python interpreted not read this line.

Let’s do one small task.
Variable Declaration Task: We check in a patient named John Toe. He’s 20 years old and is a new patient.

name = 'John Toe'
Age = 20
is_new_patient = True

As of now we successfully learn how to declare the variable in python. Next, we learn about how to get input from users.

Instead of print() method use input() method to get the input from the user.


name = input('What is your name? ')
print('Hey! ' + name)
In your terminal, interpreted python will wait for your input. In my case, I type John Carter and then hit enter.

Task 2: Ask two questions – Person’s name and his favorite color. Print the output like “John Toe like violet”.

name = input('What is your name? ')
Color = input('what is your favourite color? ')
print(name + ' like ' + color);
The output of program – python input/print

Type conversion

Type conversion is used to define a variable for calculation. If the number is in string format we need to convert the number string into the integer type.


birth_year = input('Your birth year? ')
age = 2020 - birth_year
print('Your age is ' + age)
You will get an error – TypeError: Unsupported operand type(S) for int and str

You get input from the terminal 1994 and the type of 1994 is string identified with the use of type() method.

You get an error in line 20 in the file. It will be shown in the terminal due to the type differentiation. So how to solve this problem. We need to convert the type from string to integer.

How to convert the string to integer

int() – method is used to convert the typed string to an integer.
str() – method is used to convert the integer type to string type.


birth_year = input('Your birth year? ')
age = 2020 - int(birth_year)
print('Your age is ' + str(age))
output: Type conversion example

In the next article let see the strings in python. Go the next continuation on the menu.

Basics of python tutorial 2

Open your PyCharm or your favorite IDE. Click to create a new project and name your project.

Give your project name and check the base interpreter has the current version. If you need another version, you can select the other version from the list.

Create a first python program

Name your file. In my case

Now let’s start to learn the code first.

How to console or print the value in the python

file name:

print('Hi! welcome to helperscript');

print(data) => print function helps to print or console in terminal output. It is used to identify whether the data passed are correct or incorrect.

data => you can pass data that you want to output. When your data is a string. String declaration with a single quote or either double quote.

Eg: print(“hello”) is equal to print(‘hello’)
Then Run the file from the menu Run. It will show configuration settings. As of now we just run the file. So just click on the app.

After Run the file. The below terminal will open and show the output like below.

output in console python

Python code gets executed line by line from the top.

Print the string with the multiplication

file name:

print('Hi! welcome to helperscript')
print('*' * 5)
output of print(‘*’ * 5)

In python, the String data type can be generated and printed multiple times with an asterisk.

So the python is powerful for AI, Automation, desktop application, and web application. 

Let us see more new topics in python in the next article. Go to the menu of Python and find the next tutorial for continuation…

Python 3 tutorial step by step learning through free courses


Python is one of the most popular languages nowadays.

Python has the ability to do

  1. Automation
  2. AI (Artificial Intelligence)
  3. Applications
  4. Websites

We talk about all the core concepts in python and then we build three(3) python projects together.


Django administration



Let’s start the course for the absolute beginners.



  1. Go to
  2. Click on downloads
  3. Click the Download button for the latest version

In windows simply click and open the downloaded file. Make sure you check Add path to the variable.

For Mac, Just continue and Agree with the license agreement and install it.

Install python in mac

Next, we are going to install a code editor. PyCharm ( is one of the best code editors for python. It fully depends on you. You can use another editor too.

Download and install pyCharm on your computer depends on your OS.

Windows => click next => next => and install

Mac => drag and drop the pyCharm to the application to install.

Choose your theme, Most of them use Dracula or blacky themes to protect their eyes. Now open your pyCharm application.

Congratulations, you are now successfully downloading and installing everything for python to learn.

Go to the python menu on top and see the continuation tutorial in the python.

Angular automated testing

In this article, we will learn more about automated testing in angular.

What is automated testing?
It is type of testing software without humans with lesser time. It helps you to catch the defects before releasing the software.

How to write a test coding in angular?
Before jumping into the test coding. Let see the different type of testing in angular.

Type of Testing in angular

  • Unit Testing (UT)
  • Integration Testing (IT)
  • End to End Testing (e2e)

Unit Testing
Test a component in Isolation, without external resources (e.g. file system, database, API endpoints).

  • Easiest to write
  • Superfast
  • Don’t give us much confidence.

Integration Tests
Test a component with external resources (e.g. file system, database, API endpoints)
Integration tests: component + template
Unit tests: component

End-to-end Tests

Test the entire application as a whole.

  • More confidence
  • Very slow
  • Very fragile

Let’s see the fundamental of Unit Testing
Tests are first-class citizens.

Clean Coding Practices

  • Small functions/ methods (10 lines of code or less)
  • Proper naming
  • Single responsibility

Example of Unit testing in angular

if(number < 0){
return 0;
return number + 1;

Use jasime javascript library to write the test code.
Common function using in angular is
describe() // suite
it() // spec
expect() // ecpected value

compute.spec.ts // test file

import {compute} from '.compute'
describe('compute', () =>{
it('should return O if input is negative', () => {
const result = compute(-1);

Run the code with “ng test compute”

 As you can see in the above image "Executed 1 of 1 success".
Run the ng test command create a browser instantiated and show like below. Karma will connected.
angular karma listener

After click on debug and see it in the console will reply the same of the test result. You can save it in a file for your track.

debug angular

This is how Unit testing will write. In next article will see the integration testing and later end to end testing.

Top ten Javascript tricks part 5

“for in” vs “for of”

for(a in 'ab'){

for(a of 'ab'){

Record Timing

setTimeout(() => console.log, 1000)
// result: timer: 0.056884765625ms

Fibonacci sequence algorithm in Javascript

//while loop
function fibonacci(num){
let a = 1, b = 0 , temp;
while(num >= 0){
temp = a;
a = a + b;
b = temp;
return b;

//Recursive solution
function fibonacci(num){
if(num <= 1) return 1;
return fibonacci(num - 1) + fibonacci(num - 2);

function fibonacci(num, memo){
memo = memo || {};
if(memo[num]) return memo[num];
if(num <= 1) return 1;
return memo[num] = fibonacci(num - 1, memo) + fibonacci(num - 2, memo)

One time event listeners in Javascript

const button = document.getElementById('button');

button.addEventListener("click", () => {
console.log('I will fire only once');
}, {once: true})

Private field declaration in es6 class

In Es6, private class fields are defined using a hash # prefix.
You can start using them today with babel7 and stage 3 preset

class Something{

constructor() {
this.#property = "Test property";

const instance =  new Something();
//Result: undefined

Code validator in new Es2020 features are now finalized

//old way
user && user.address && &&

// do this Es2020 beatury

Pipeline Operator

The experimental pipeline operator |> (current stage at 1) pipes the value of an expression into a function.
This allows the creation of chained function calls in a readable manner.
The result is syntactic sugar in which a function call with a single argument.
As of now, there is no Browser compatibility.

function doubleSay(str){
return str +", "+ str

function capitalize(str){
return str[0].toUpperCase() + str.substring(1)

function exclaim(str){
return str + '!'

let result = exclaim(capitalize(doubleSay("helperscript")))
console.log(result) // "Helperscript helperscript!"

result = "helperscript" |> doubleSay |> capitalize |> exclaim
console.log(result) // "Helperscript, helperscript!"

Static Vs Dynamic Import

import React from 'react';
// module exported with default keyword

import { FC } from 'react';
// module exported without default keyword

// Dynamic import
import('path/to/module.js').then((module) =>{

//or inside an async function
const module = await import('path/to/module.js');

Javascript padStart() and padEnd()

padStart() – The padding applied from start of string
padEnd() – Then padding applied from end of string

'helperscript'.padStart(14); // "  helperscript"
// if padString given
'helperscript'.padStart(14, '#') // "##helperscript"

//if padString not given
'helperscript'.padEnd(14) // "helperscript  "

// if padString given
'helperscript'.padEnd(14, '#') // "helperscript##"

String() Vs .toString() in javascript

The String () method converts anything into a string.
The toString() method converts numbers and booleans to a string.

String(68) // "68"
String(null) // "null"
String(undefined) //  "undefined"
String(true) // "true"

// toString()
(68).toString(); //"68"
(true).toString(); // "true"
(null).toString(); // TypeError
(undefined).toString(); // TypeError

But Unlike the String() method, the .toString() method will throw a TypeError, when used with null or undefined

Have a great day! Comment if any queries.