DEV Community: Asad Ullah

JavaScript more efficient and readable code for make a calculator with only 20 lines with

Asad Ullah — Sat, 21 Jan 2023 17:46:02 +0000

Eval Function for a Calculator

Click Here for visit the calculator and its code
This is very very best way to improve and make efficient for our code. The eval() function is very helpful to make efficient, readable and maintainable. As we know about eval() function the eval() is a function property of the global object. The argument of the eval() function is a string. It will evaluate the source string as a script body, which means both statements and expressions are allowed. It returns the completion value of the code. For expressions, it's the value the expression evaluates to.

Comment me if you have impressive by this calculator.

Click Here for visit the calculator and its code

JavaScript Tips and Tricks: difference between VAR and LET variables Concept.

Asad Ullah — Tue, 13 Sep 2022 11:49:52 +0000

Difference between `VAR and LET`

As we know in order to declare a variable in JavaScript we have two options either declare with var or declare with let. Now the question is when to use var and when to use let. What are the major difference between both.

The main difference between let and var is that scope of a variable defined with let is limited to the block in which it is declared while variable declared with var has the global scope. So we can say that var is rather a keyword which defines a variable globally regardless of block scope.

The scope of let not only limited to the block in which it is defined but variable with let also do not get added with global window object even if it get declared outside of any block. But we can access variable with var from window object if it is defined globally.

Due to limited scope let variables are usually used when there is limited use of those variables such as in for loops, while loops or inside the scope of if conditions etc while var variable is used when value of variable need to be less change and used to accessed globally.

Follow this code to check the differentiate between VAR and LET

let a = 'hello'; // globally scoped
var b = 'world'; // globally scoped
console.log(window.a); // undefined
console.log(window.b); // 'world'
var a = 'hello';
var a = 'world'; // No problem, 'hello' is replaced.
let b = 'hello';
let b = 'world'; // SyntaxError: Identifier 'b' has already been declared

JavaScript Const re-assignment in Array with full Concepts

Asad Ullah — Thu, 01 Sep 2022 19:40:36 +0000

Variable `Const`

As we know that the "const" keyword was included in ES6(2016). The const variable cannot be reassign the value. JavaScript const variables must be assigned a value when they are declared like this...

const firstName = "Sayyed Asad";

But this is a general rule, always declare a variable with const unless you know that the value will change.
Use const when you declare...

New Array
New Object
New Function
New Regexp

How would be re-assignment of const in an array and what's the reason about that behind the concept of this topic?

const developers = ['Sayyed Asad', 'Nisar', 'Toqeer'];
developers[2] = 'Jonas';

So, first of all as a good experience in the JavaScript. I should be inform you here is const is manipulate. But I was still able to change one element of the Array here from Toqeer to Jonas.That is only primitive value. But an Array is not a primitive value. And so we can actually always change it so we can mutate it.

If you have some knowledge from my article. So, please follow me and share this post and like and comment on bellow this post.

HTML Tips And Trick For Everyone

Asad Ullah — Wed, 24 Aug 2022 17:38:26 +0000

Title Bar `Add Icon`

The many beginners have no any idea to about title bar's icon. But this is vary simple trick to add any icon on title bar just download any letter image for practice and do follow my code.

<head>
  <title>Sayyed Asad Ullah</title>
  <link rel="icon" href="letter-A.png">
</head>

Add Video in Website `Video Tag`

When we need to add a video in our site. So then we need to use video element. But in HTML 5 we can add a video using with video element. But in this case we apply using with source element and source attribute. Because the reason is about that to add a video we need both these mark code.

`html

video and audio `controls attribute`

We can control our audio and video volume as low or high as we want with using controls attribute.In addition, we can also pause or play our video and audio with using controls attribute.

`html

Meta tag `SEO META tag`

Add meta descriptions in the head of your Html to have an indirect impact on search engine optimization meta description represents the text that appears beneath the site name on search engine result page. like when you search on google any text or any content.