Javascript Introduction
Comments in Javascript
Javascript Variables
Difference between var, let and const in Javascript
Datatypes
Assignment Operators
Logical Operators
Comparison Operators
Actions alert, prompt & confirm

Javascript Flow Control
Conditional Statements in Javascript
Nullish coalescing operator in Javascript
Break and Continue in Javascript
Loops in javascript
for loop in Javascript
while loop

Javascript Functions
Javascript Functions
JavaScript Arrow Function

Javascript Objects
Javascript Objects

Javascript Array
Javascript Arrays

Javascript Error Handling
Error Handling in Javascript

Javascript ES6
Set
Javascript Spread Operator
Rest Parameter in Javascript

Javascript Asynchronous
Javascript Callback Function
Promises in Javascript
Promise Chaining
Async-Await in Javascript

Javascript DOM
DOM Document
DOM Elements
DOM Attributes
DOM Manipulation
DOM Node Lists
Javascript Events
DOM Traversing Elements
DOM EventListener

Javascript Class
Classes in javascript
Class Inheritance

Javascript Design Principles
SOLID - The Single responsibility principle in javascript
SOLID - Open-Closed principle in Javascript

Other Topics
Javascript Hoisting
Filter, Map and Reduce functions in Javascript
Closure in Javascript
Optional chaining operator in Javascript
Consoling in table format in javascript
Fetch API in Javascript
HTML web Storage API
Checking the online or offline status of the browser

Comments in Javascript

Published on: July 03, 2021 By T.Andrew Rayan

Comments in javascript is used by the developer to give explanation to the code. It describes what the code or the function doe. The comments does not execute.

There are 2 types of comments

1) Single-line comments

2) Multi-line comments

Single-line Comments:

The single line comments are represented by the notation //.

The // notation followed by the string comments will not be executed. It works only for a single line.

Example for single line comments

// function to add two variable
function add(a,b){
	return a+b;
}

We can also use the single line comment to the end of the code to explain its purpose.

var discountPercentage; // variable used to get discount percentage.

Multi-line Comments:

Multi-line comments have one or more lines within a set of comment delimiters. The delimiters starts with /* and ends with */ delimiter notation.

Like single-line comments, multi-line comments also will not execute by the program.

Example for mulit-line comments

/*
Function used to calculate discount
discount parameter is the discount %
total parameter is the total amount
*/
function calculateDiscount(discount, total) {
	return (total*discount/100);
}

In the above code we have a function calculateDiscount and the comments explains about the operation performed by it and the description about the parameters.

So now when the other developer works on the code, he would be able to understand its purpose. Though the function is small and clear explains its operation not all the functions will be simple as this. So in such cases the comments will be helpful and saves most of the time in understanding the code.

Comments in Javascript

Published on: July 03, 2021 By T.Andrew Rayan

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