11 Tips for Improving Your JavaScript Performance

Tips and tricks to get the most out of your JavaScript

  1. Loops — Avoid them if not needed
  2. Minimize DOM access in order to have a more responsive page
  3. Asynchronous Programming
  4. Detection of Problems
  5. Scoping of Variables
  6. Event Delegation
  7. Object Caching
  8. Limiting Memory Usage
  9. JavaScript Delay loading
  10. Say NO to Memory Leakages
  11. Use Various Optimizations

JavaScript has become one of the leading scripting languages. JavaScript is everywhere — on the client-side as well as on the server-side. It is also one of the most popular languages used on GitHub.


Loops — Avoid them if not needed

Looping in JavaScript is not considered a good thing since it puts extra strain on the browser. The amount of code inside the loops should be as small as possible. The less work we do in the loop the faster will be our loop. Moreover, we can also adopt simple tricks like, rather than reading the length at each iteration of the loop, we can store the array’s length in a different variable. This could go a long way in optimizing our code and run things in a more efficient manner.

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Minimize DOM access in order to have a more responsive page

Any interaction that takes place outside the JavaScript native environment results in a significant amount of performance lag and unpredictability. For example, if the host browser is interacting with the DOM object multiple times outside the environment, it will cost us performance since the browser has to refresh every time. To avoid this, we should be minimizing DOM access. There are a few ways by which we can achieve this. For example, we can store references to the browser objects, or we can decrease the overall DOM traversal trips.

Asynchronous Programming

In any application, we need to make several internal calls to multiple APIs to fetch data. One way of doing this is to have separate middle-ware for each functionality. However, JavaScript is single-threaded and has lots of synchronous components. These components have the capability to freeze the application.

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JavaScript’s async.js feature comes handy in these kinds of scenarios. It helps in the efficient management of asynchronous codes. This causes async code to get pushed to an event queue where it fires after the execution of all other codes. However, even with the JavaScript’s async feature, there’s still a possibility of using an external library that could inadvertently lead to synchronous blocking calls. And this could have an adverse effect on the overall performance of the application.

Hence to tackle these in the best way, we should always use asynchronous APIs in our code. However, we also need to keep in mind the intricacies of async programming, since it is often challenging for the freshers.

Detection of Problems

Lighthouse is a tool widely used for web pages. It helps in accessibility, audit performance, SEO, and other best practices. Similarly, Google PageSpeed is built to help JavaScript developers to understand areas of improvement and performance optimizations of a website.

In Chrome’s main menu, there’s an option of ‘More Tools’ which shows you the memory and the CPU usage by each tab. We can also use the Performance view in either Chrome or Firefox to carry out even more detailed analysis. With this we are able to analyze various metrics, for example:

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If we want to dive deeper, we can use the Navigation Timing API. It provides data that can be used to measure the performance of a web site.

Scoping of Variables

Whenever we call a certain function, the variables that are used to define that function are stored inside. Variables can be categorized into two types.

  • Local variable: — Variables that are defined only within themselves.
  • Global variable: — Variables that are used throughout the script.

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During function call, the JavaScript compiler does a scope lookup of the variables that are being used. With the increase in the number of scopes in the scope chain, there’s also an increase in the amount of time taken to access variables that are outside the current scope.

This is the reason why the engine takes a long time to access a global variable as compared to that of a local variable. This means if we define most of the variables locally, the time required for the variable search will decrease rapidly. Eventually, it will boost the overall performance of the application.

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11 Tips for Improving Your JavaScript Performance
Ray  Patel

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top 30 Python Tips and Tricks for Beginners

Welcome to my Blog , In this article, you are going to learn the top 10 python tips and tricks.

1) swap two numbers.

2) Reversing a string in Python.

3) Create a single string from all the elements in list.

4) Chaining Of Comparison Operators.

5) Print The File Path Of Imported Modules.

6) Return Multiple Values From Functions.

7) Find The Most Frequent Value In A List.

8) Check The Memory Usage Of An Object.

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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.

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Rahul Jangid

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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

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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.

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Eldora  Bradtke

Eldora Bradtke

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JavaScript Memory Management System

The main goal of this article is to help to readers to understand how memory management system performs in JavaScript.

I will use a shorthand such as GC which means Garbage Collection. When the browsers use Javascript, they need any memory location to store objects, functions, and all other things. Let’s deep in dive that how things going to work in GC.

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The JavaScript Engine’s Garbage collector’ looks out for objects which are unreachable and also removed from the memory.

So I will share an example below and show you steps that will be needed to work with GC.

var number = 50;                // allocates memory for a number

var string = 'textual data';  // allocates memory for a string
var object = {x: 10};         // allocates memory for an object
var x= [10, null, 'abra'];     // allocates memory for the array
function f(x) {               // allocates memory for a function
return x * 2;
}                              

The example shows how JavaScript allocates memory for the variables when they declare. But when the memory is no longer needed, the allocated memory will be released. GC finds the memory no longer used by the application and releases it. But the main question is that how GC finds the memory no longer used?

The basic algorithm for doing that is called “mark-and-sweep”.

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