Amara  Legros

Amara Legros

1594514983

Javascript Arrays: From O(n*2) to O(n) — Code Examples

In my last article, I gave a brief of time complexities of some popular Javascript array methods. In this article, I will give three code examples of how to improve the performance in array solutions.

Below are examples of O(n*2) solutions to common array problems. We will explore other options for solving with the aim of improving performance.

Example One: Return Duplicate Elements in an Array.

Problematic: For each element, loop through the array to see if there is another element like it. If yes, push to another array, if no, don’t.

GitHub Gist with less performant code

The above solution is O(n*2). For every first element in the array, we take another loop through the array to find if it has a match. For a few elements, it may not be slow, but as you increase the items (i.e 100k elements) you begin to see the slowness.

Performant: Create a map, loop through array and check map, if map has element already, push to return array.

#performance #arrays #javascript #big-o-notation

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Buddha Community

Javascript Arrays: From O(n*2) to O(n) — Code Examples
Amara  Legros

Amara Legros

1594514983

Javascript Arrays: From O(n*2) to O(n) — Code Examples

In my last article, I gave a brief of time complexities of some popular Javascript array methods. In this article, I will give three code examples of how to improve the performance in array solutions.

Below are examples of O(n*2) solutions to common array problems. We will explore other options for solving with the aim of improving performance.

Example One: Return Duplicate Elements in an Array.

Problematic: For each element, loop through the array to see if there is another element like it. If yes, push to another array, if no, don’t.

GitHub Gist with less performant code

The above solution is O(n*2). For every first element in the array, we take another loop through the array to find if it has a match. For a few elements, it may not be slow, but as you increase the items (i.e 100k elements) you begin to see the slowness.

Performant: Create a map, loop through array and check map, if map has element already, push to return array.

#performance #arrays #javascript #big-o-notation

Lowa Alice

Lowa Alice

1624388400

JavaScript Arrays Tutorial. DO NOT MISS!!!

Learn JavaScript Arrays

📺 The video in this post was made by Programming with Mosh
The origin of the article: https://www.youtube.com/watch?v=oigfaZ5ApsM&list=PLTjRvDozrdlxEIuOBZkMAK5uiqp8rHUax&index=4
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Thanks for visiting and watching! Please don’t forget to leave a like, comment and share!

#arrays #javascript #javascript arrays #javascript arrays tutorial

Hertha  Walsh

Hertha Walsh

1600871280

Increase Performance of React Applications Via Array JavaScript Methods

We know the array methods of javascript. We used it in simple programming, right? But today we will see how to use it in real life programming.

We will create a simple event management application in the react to add, update, and delete an event. I have already created an application. You guys just have to clone it and run it then we will see how to increase the performance of it by implementing array methods in it.

Clone the following repository then you will have a simple event management application. Later on, step by step, we will add code in it to see how array methods will help to increase the performance.

#react #react-native #reactjs #javascript #arrays #javascript-arrays #programming #coding

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

Javascript Array From Example | Array.prototype.from()

Javascript array from() is an inbuilt function that creates a new, shallow-copied array instance from an array-like object or iterable object.

The Array .from() lets you develop Arrays from the array-like objects (objects with a length property and indexed items) or  iterable objects ( objects where you can get its items, such as Map and  Set).

The Array from() function was introduced in ECMAScript 2015.

Javascript Array From Example

Array.from() method in Javascript is used to creates a new  array instance from a given array. If you pass a  string to the Array.from() function, then, in that case, every alphabet of the string is converted to an element of the new array instance. In the case of integer values, a new array instance simply takes the elements of the given Array.

The syntax of the Array.from() method is the following.

Syntax

Array.from(arrayLike[, mapFn[, thisArg]])

#javascript #ecmascript #javascript array from #array.prototype.from