JavaScript Coding Style and Comments (Best Practice)

As a programmer /developer, our code must be as clean and easy to read. We need to write comments to understand the codes for others.

Coding Style

function pow(num, sup) {
let result = 1;

Curly Braces

Bad practice of writing JavaScript code:-

if (n < 0) {alert(‘${num} is not valid’);}
or,
if (n < 0)
alert(‘${num} is not valid’)
or,
if (n < 0) alert(‘${num} is not valid’);

Best practice to use Curly Braces:-

if (n < 0) {
alert(‘${num} is not valid’); // 2 space indentation
}

Line Length

Long Horizontal code is bad. It’s very irritating for code readers.

const str = “JavaScript is a lightweight, interpreted, or just-in-

in if statement:

if ( num !== condition1 && sup ≥ 0 && num ≥ 1 ) { 
return pow(num, sup);
}

You need to split the long code.

const str = `JavaScript is a lightweight, interpreted, or 
just-in-time compiled programming language
with first-class function`;

for if statement:

if (
number !== condition1 &&
super ≥ 0 &&
number ≥ 1
) {
return pow(num, sup);
}

Code Indentation

There are two types of Code Indentation.
1. Horizontal Code Indentation
2. Vertical Code Indentation
Horizontal Indents: 2 or, 4 spaces for horizontal indentation is best practice for writing code.

for (let i = 0; i < sup; i++){
result *= number; // 2 spaces
}
or,
for (let i = 0; i < sup; i++){
result *= number; // 4 spaces
}

Vertical Indents: Splitting the code into logical blocks using empty lines
function pow(num, sup) {
let result = 1;

for (let i = 0; i < sup; i++){
result *= number;
}

return result;
}

Semicolons

You must need to use a semicolon after each code statement.

let num = prompt(“x?”, “”);
let sup = prompt(“n?”, “”);

Nested Code

Always Try to avoid Nesting code too many levels deep.
You can use the continue or, return keyword to avoid nested code.

use of continue keyword

for(let i = 0; i < n; i++) {
if(i % 2 === 0) {
// code
}
}

Avoid nesting with continue keyword:-

for(let i = 0; i < 10; i++) {
if(i % 2 === 0) continue;
// code
}

use of return keyword

function pow(num, sup) {
if (num < 0) {
console.log('Please Enter Positive Number!');
} else {
let result = 1;

avoid nesting using the return keyword

function pow(num, sup) {
if (num < 0) {
console.log('Please Enter Positive Number!');
return;
}

let result = 1;