Removing Duplicates with Map in JavaScript

It is quite common to use Set to remove duplicate items from an array. This can be achieved by wrapping an existing array into Set constructor and then transforming it back into array:

const arr = [1, 2, 'a', 'b', 2, 'a', 3, 4];
	const uniqueArr = [...new Set(arr)];

	console.log(uniqueArr); // [1, 2, "a", "b", 3, 4]

This works great for arrays of primitive values, however when applying the same approach to array of arrays or objects, the result is quite disappointing:

const arr = [[1, 2], {'a': 'b'}, {'a':2}, {'a':'b'}, [3, 4], [1, 2]];
	const uniqueArr = [...new Set(arr)];

	console.log(uniqueArr); // [[1, 2], {'a': 'b'}, {'a':2}, {'a':'b'}, [3, 4], [1, 2]]

This is because Set compares non-primitive values by reference and not by value, and in our case all values in array have different reference.

#web-development #maps #javascript-tips #javascript #react

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Removing Duplicates with Map in JavaScript

Removing Duplicates with Map in JavaScript

It is quite common to use Set to remove duplicate items from an array. This can be achieved by wrapping an existing array into Set constructor and then transforming it back into array:

const arr = [1, 2, 'a', 'b', 2, 'a', 3, 4];
	const uniqueArr = [...new Set(arr)];

	console.log(uniqueArr); // [1, 2, "a", "b", 3, 4]

This works great for arrays of primitive values, however when applying the same approach to array of arrays or objects, the result is quite disappointing:

const arr = [[1, 2], {'a': 'b'}, {'a':2}, {'a':'b'}, [3, 4], [1, 2]];
	const uniqueArr = [...new Set(arr)];

	console.log(uniqueArr); // [[1, 2], {'a': 'b'}, {'a':2}, {'a':'b'}, [3, 4], [1, 2]]

This is because Set compares non-primitive values by reference and not by value, and in our case all values in array have different reference.

#web-development #maps #javascript-tips #javascript #react

Rahul Jangid

1622207074

What is JavaScript - Stackfindover - Blog

Who invented JavaScript, how it works, as we have given information about Programming language in our previous article ( What is PHP ), but today we will talk about what is JavaScript, why JavaScript is used The Answers to all such questions and much other information about JavaScript, you are going to get here today. Hope this information will work for you.

Who invented JavaScript?

JavaScript language was invented by Brendan Eich in 1995. JavaScript is inspired by Java Programming Language. The first name of JavaScript was Mocha which was named by Marc Andreessen, Marc Andreessen is the founder of Netscape and in the same year Mocha was renamed LiveScript, and later in December 1995, it was renamed JavaScript which is still in trend.

What is JavaScript?

JavaScript is a client-side scripting language used with HTML (Hypertext Markup Language). JavaScript is an Interpreted / Oriented language called JS in programming language JavaScript code can be run on any normal web browser. To run the code of JavaScript, we have to enable JavaScript of Web Browser. But some web browsers already have JavaScript enabled.

Today almost all websites are using it as web technology, mind is that there is maximum scope in JavaScript in the coming time, so if you want to become a programmer, then you can be very beneficial to learn JavaScript.

JavaScript Hello World Program

In JavaScript, ‘document.write‘ is used to represent a string on a browser.

<script type="text/javascript">
	document.write("Hello World!");
</script>

How to comment JavaScript code?

  • For single line comment in JavaScript we have to use // (double slashes)
  • For multiple line comments we have to use / * – – * /
<script type="text/javascript">

//single line comment

/* document.write("Hello"); */

</script>

Advantages and Disadvantages of JavaScript

#javascript #javascript code #javascript hello world #what is javascript #who invented javascript

Hire Dedicated JavaScript Developers -Hire JavaScript Developers

It is said that a digital resource a business has must be interactive in nature, so the website or the business app should be interactive. How do you make the app interactive? With the use of JavaScript.

Does your business need an interactive website or app?

Hire Dedicated JavaScript Developer from WebClues Infotech as the developer we offer is highly skilled and expert in what they do. Our developers are collaborative in nature and work with complete transparency with the customers.

The technology used to develop the overall app by the developers from WebClues Infotech is at par with the latest available technology.

Get your business app with JavaScript

For more inquiry click here https://bit.ly/31eZyDZ

Book Free Interview: https://bit.ly/3dDShFg

#hire dedicated javascript developers #hire javascript developers #top javascript developers for hire #hire javascript developer #hire a freelancer for javascript developer #hire the best javascript developers

Niraj Kafle

1589255577

The essential JavaScript concepts that you should understand

As a JavaScript developer of any level, you need to understand its foundational concepts and some of the new ideas that help us developing code. In this article, we are going to review 16 basic concepts. So without further ado, let’s get to it.

#javascript-interview #javascript-development #javascript-fundamental #javascript #javascript-tips

Coy  Roberts

Coy Roberts

1600510680

Definitive Guide to Understand Javascript Array reduce()

Javascript array reduce() is an inbuilt method that is used to apply a function to each element in the array to reduce the array to a single value. The reduce() function executes the provided function for each value of an array from left-to-right. The return value of a function is stored in an accumulator.

Understanding Javascript array reduce()

JavaScript array reduce() is one of the pioneer function of functional programming. The reduce() method accepts two parameters, the total and the current value. If you want to add all the values of an array, then use the array reduce() function.

It is similar to both  Javascript map() and  Javascript filter() but, it differs in the callback arguments.

The callback now receives an accumulator (it accumulates all the return values. Its value is the accumulation of a previously returned accumulations), a current value, a current index, and finally, the whole array.

#javascript #javascript map #javascript filter #javascript array reduce