DEV Community: Mohan Mogi

“JavaScript Array Methods Explained Simply”

Mohan Mogi — Thu, 09 Apr 2026 05:17:33 +0000

ARRAY:
An array is an object type,it is used for storing data collections.Multiple values store in a single variable.

FEATURES OF JAVASCRIPT ARRAYS are:

ELEMENT
An array a list of values are known as elements.
ORDERED
Array elements are ordered
Based on their index.
ZERO INDEXED
The first element is index 0,
Second element is 1.
HETEROGENEOUS
Arrays can store elements of different datatypes.
(Strings,numbers,objects and other arrays)

WHY USE ARRAY:

let a = 10;
let b = 20;
let c = 30;
This is ok for 3 variables,how can manage 200,300 variables?.So use array.An array can store many values under a single name,can acces the values by referring to an index number.

Array syntax
let numbers = [10, 20, 30];

console.log(numbers[1]);
Output 20

BASIC ARRAY METHODSS

Array length
Array toString() – Convert to string
Array at() –
Array join()
Array pop() – Remove last element
Array push() – Add at end
Array shift()
Array unshift()
Array isArray()
Array delete()
Array concat()
Array copyWithin()
Array flat()
Array slice()
Array splice()
Array toSpliced()

1.Array length
Array length means length property returns the length(count,size)of an array.

Explanation:
🔹The array has 3 values,so length is 3.
🔹Even though index starts at 0, length counts from 1.

2.Array tostring()
The tostring methods returns the elements as of array commas as a seperated string.

Explanation
🔹The .toString() method converts the array into a string
🔹It automatically adds commas ( , ) between values
🔹output (1o,20,30)

3.Array at()
The at() methods returns an indexed element from an array.Including negative index.

Explanation
🔹at(0) → first element
🔹at(1) → second element
🔹at(2) → third element
🔹output
10
20
30

4.Array join()
This method is joins all array element into a string.its react like array tostring(),but add in specify the seperator.

Explanation
🔹 Converts array to string
🔹 Does not change original array
🔹 output( 10 20 30 )

Add specify seperator

Explanation
🔹 add in specify seperator
🔹 output(10*20*30)

5.Array pop()
Array pop method remove the last element from an array.
The pop() method returns the value that was "popped out":

Explanation
🔹Removes the last element 30
🔹Returns the removed value 30
🔹Updates the array → [10, 20]
🔹Output:
30
[ 10, 20 ]

6.Array push()
Array push() method is one or more new element add to an array at the last.

Explanation
🔹Adds element to the end
🔹Updates the original array.

push() returns the new arraylength.
push()return value

Explanation
🔹Adds elements to the end
🔹Changes the original array
🔹Returns new length

7.Array shift()
This method is remove fisrt element from an array and shifts all other element to a lower index.The shift() method returns the value that was "shifted out":

Explanation
🔹Removes the first element → 10
🔹Returns the removed value → 10
🔹Updates the array → [20, 30]

8.Array unshift()
The unshift() method is used to add one or more elements to the beginning (start) of an array.

Explanatioon
🔹Adds element at the start
🔹Moves existing elements to the right

The unshift() method returns the new array length:

Explaation
🔹 Adds elements to the beginning
🔹 Changes the original array
🔹 Returns new length

9.Array isArray()
Array.isArray() is used to check whether a value is an array or not.

Explanation
🔹true means its array
🔹false means its not array

10.array delete()
It is a delete keyword, but it is not recommended for arrays
Because it removes the value but keeps an empty slot (hole).

Explanation
🔹Index still exists
🔹Creates empty (undefined) space

11.Array concat()
The concat() method creates a new array by merging (concatenating) existing arrays:

Explanation:
🔹arr1 contains [10, 20]
🔹arr2 contains [30]
🔹concat() joins both arrays and returns a new array
🔹Original arrays are not changed

JAVASCRIPT OBJECT FUCTIONS

Mohan Mogi — Wed, 08 Apr 2026 05:58:13 +0000

OBJECT CONSTRUCTOR FUNCTIONS:
The constructor method for creating and initailizing object.Sometimes create many object of the same type,to create an objecct constructor function.constructor functions with an first letter start with an upper case letter.

OBJECT LEARN CRUD METHODS

Mohan Mogi — Tue, 07 Apr 2026 06:30:43 +0000

OBJECT:
An object is stores a collection of key value pairs.
key is property name,value is store any datatypes.

CRUD:
C-Create (create object)

R-Read (read object)

U-Update (update values in object)

D-delete (delete values in object)

JavaScript Functions Tutorial:

Mohan Mogi — Mon, 06 Apr 2026 07:33:40 +0000

what is function ?
Function are fundamental in all programming language.funtions are reusable code blocks designed to particular task.Instead of writing the same code again and again, you can define it once and call it whenever needed.

Why use Functions ?
code wrrite once run many times.Easy to code make to read and maintain.

Structure of function
A function can be created with the keyword,name and parentheses..The code that needs to be executed written inside the curly brackets.To run a function using call it's name,keyword.

Example:

keyword,name name()
output inside the curly brackets (abcd)
call name()

Array in javascript

Mohan Mogi — Fri, 03 Apr 2026 07:47:56 +0000

Array is used to store multiple values in a single variable.
An Array is an object type designed for storing data collections.

Uses of array:
1)Store multiple values in one variable
2(Easy to access and manage data
3)Useful for loops and data processing

Example;
code to add programs

Javascript whileloop

Mohan Mogi — Fri, 27 Mar 2026 06:38:15 +0000

What is a While Loop in JavaScript?
A while loop in JavaScript is used to repeat a block of code as long as a condition is true.

It is helpful when you don’t know how many times the loop should run in advance.

let i = 1;

while (i <= 5) {
console.log(i);
i++;
}
Output
1
2
3
4
5

Javascript operators

Mohan Mogi — Wed, 25 Mar 2026 08:59:25 +0000

JavaScript operators are special symbols used to perform operations on variables and values. They are the foundation of writing logic in JavaScript programs.

Types of JavaScript types:
1) Arithmetic operators
Arithmetic operators Used to perform mathematical operations.

console.log(a + b);
Addition
console.log(a - b); Subtraction
console.log(a * b); Multiplication
console.log(a / b);
Division
console.log(a % b);
Modulus
console.log(a ** b);
Exponent
2) Assignment Operators
Assignment operators Used to assign values to variables.
x += 5;
x -= 3;
x *= 2;
x /= 2;

3) Comparison Operators
Comparison Operators Used to compare two values and return true or false.

console.log(a == b); true
console.log(a === b); false
console.log(a != b); false
console.log(a > 5); true

4)Logical Operators
Logical Operators Used to combine multiple conditions.

console.log(age > 18 && age < 30);
AND
console.log(age > 18 || age < 10);
OR
console.log(!(age > 18)); NOT

5)Increment and Decrement
Increment and Decrement Used to increase or decrease values.

i++; Increment
i--; Decrement

6)Ternary Operator
Ternary Operator Short form of if-else.
let age = 20;

let result = (age >= 18) ? "Adult" : "Minor";
console.log(result);

7)String Operator
String Operator Used to combine strings.

let first = "Hello";
let second = "World";

console.log(first + " " + second);

8)Type Operator
Type Operator Used to check data type.

Understanding JavaScript Data Types: A Beginner’s Guide

Mohan Mogi — Wed, 25 Mar 2026 08:24:31 +0000

SCRIPT:
Script is runs automatically and it is does not need full compilation

WHY JAVASCRIPT CALLED JAVASCRIPT?
Javascript original name was MOCHA,after changed to livescript.It was created in 1995 by Brendan Eich at Netscape.Later renamed javascript.At that time, Java was very popular.So Netscape used the name “JavaScript” as a marketing strategy to attract developers.

DATATYPES:
It's define what kind of value a variable can hold and how value can be used it.

The Role of Data Types:
1.Store data correctly
2.Perform Valid operations
3.Avoid errors

TYPES OF DATATYPES IN JAVASCRIPT:
They are two types of datatypes.
1.PRIMITIVE Data Types
2.NON-PRIMITIVE Data Types

1.PRIMITIVE Data Types
This is basic type, they Store single simple values.
Primitive data types are seven types.
1.String
( means text)
2.Number
( means numbers)
3.Boolean
( means true or false)
4.Undefined
( means no value)
5.Null
( means empty value)
6.BigInt
( means large number)
7.Symbol
( means unique identifier)

2.NON-PRIMITIVE Data Types
This is reference type, they Store multiple values complex data.
1.Object
Special object

Array
Function

Linux Installation

Mohan Mogi — Tue, 24 Feb 2026 08:36:27 +0000

Linux :
Linux is open source,it is used developers, servers, and companies worldwide.

Download ISO File:

Go to the official website
Download the latest LTS (Long Term Support) version
File size will be around 3–4 GB

Create Bootable USB:
Install rufus
1.Insert USB
2.Open Rufus
3.Select ISO file
4.Click Start

Go to settings kit locker option turn off.

Partition Create:
Go to settings disk management option.
choose to disk right clik after shrink volume.

Install Linux:

Restart computer
Press Boot key
Select USB drive
Choose “Install Linux”

You can read and continue with screen instructions.