Charles Cooper

Charles Cooper


The Complete Guide to JavaScript console.log() with Examples

Printing messages in the browser console have definitely come to rescue to all the developers out there. c**onsole.log( )** messages are like medicines for most of your diseases while debugging some wired problems in your code.

Most of the devs out there are like — Let’s print the message in the browser to know more about this issue. I’m sure that I’m not the only one doing this. 🤪

Apart from the most commonly used console.log( ) message to print the message in the browser there are plenty of different ways to make your debugging process a lot easier. Let’s take a look at them one by one with examples.

console.log( ) | info( ) | debug( ) | warn( ) | error( )

These will directly print the raw string with appropriate color based on the type of event that is provided to them.

Mastering JS console.log like a Pro
console log/info/debug/warn/error

Use placeholders

There are different placeholders that can be used as listed below
%o — which takes an object,
%s — which takes a string, and
%d — which is for a decimal or integer

Mastering JS console.log like a Pro

Add CSS to console messages

Do all of your console messages look the same? well, it won’t be the same from now on, make your logs look more catchy for what matters the most to you.

Mastering JS console.log like a Pro
Messages with colors

What to color only a specific word from the log message? Here you go 😄

Mastering JS console.log like a Pro
highlighting specific word

console.dir( )

Prints a JSON representation of the specified object.

Mastering JS console.log like a Pro

HTML elements in console

Get the HTML elements in the console just like inspecting elements

Mastering JS console.log like a Pro
HTML Elements

console.table ( )

Want to view JSON in a proper and easily understandable way?

Mastering JS console.log like a Pro
Better visualization of an array of objects huh! ) & console.groupEnd( )

It is quite possible to group the messages with the console

Mastering JS console.log like a Pro
Grouping messages

console.count( )

This function logs the number of times that this particular call to count() has been called. This function takes an optional argument label.

If label is supplied, this function logs the number of times count() has been called with that particular label.

If label is omitted, the function logs the number of times count() has been called at this particular line.

Mastering JS console.log like a Pro

console.assert( )

This comes quite handy when you only want to print some selected logs i.e. it will only print the false argument. It does nothing at all if the first argument is true.

Mastering JS console.log like a Pro

console.trace( )

This method displays a trace that shows how the code ended up at a certain point.

Mastering JS console.log like a Pro

console.time( )

A dedicated function for tracking the time taken for actions, console.time() is a better way to track the microtime taken for JavaScript executions.

Mastering JS console.log like a Pro

console.memory( )

Wondering how our JavaScript applications are using browser memory?

Mastering JS console.log like a Pro

console.clear( )

This one is the last but not the least 😁, To clear all the above console messages which you’ve learned, It’s time to destroy them with clear() command

Here is the gist for all above snippets
Link —

// time and time end
let total = 0;
for (let j = 0; j < 10000; j++) {
  total += j
console.log("Result", total);

// Memory

// Assertion
const errorMsg = 'Hey! The number is not even';
for (let number = 2; number <= 5; number += 1) {
    console.assert(number % 2 === 0, {number: number, errorMsg: errorMsg});

// Count
for (let i = 0; i < 11; i++) {

// group & groupEnd;
  console.log('Test message');;
    console.log('Another message');
    console.log('Something else');

// Table
const items = [
    name: "chair",
    inventory: 5,
    unitPrice: 45.99
    name: "table",
    inventory: 10,
    unitPrice: 123.75
    name: "sofa",
    inventory: 2,
    unitPrice: 399.50

// Clear

// HTML Element
let element = document.getElementsByTagName("BODY")[0];

// Dir
const userInfo = {"name":"John Miller", "id":2522, "theme":"dark"}

// Color
console.log('%cColor of the text is green plus small font size', 'color: green; font-size: x-small');

// pass object, variable
const userDetails = {"name":"John Miller", "id":2522, "theme":"dark"}
console.log("Hey %s, here is your details %o in form of object", "John", userDetails);

// Default 

Happy Learning! 💻 😀

#JavaScript #WebDev

What is GEEK

Buddha Community

The Complete Guide to JavaScript console.log() with Examples

Alternative libraries for Console.log() for your next JavaScript Project

If you are a JavaScript developer you must be using console.log() for debugging your JavaScript project. But do you know that there are some alternative libraries to console.log() . These libraries can be used in your next Node, React, Angular, or Vue projects. So let us see what are those libraries and how to use them.

#programming #javascript-tips #javascript #console #javascript-development

Rahul Jangid


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!");

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"); */


Advantages and Disadvantages of JavaScript

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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.

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Book Free Interview:

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Niraj Kafle


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

Cayla  Erdman

Cayla Erdman


A quick guide to JavaScript Arrays


Arrays are a structure common to all programming languages so knowing what they are and having a firm grasp on what you’re able to accomplish with Arrays will take you a long way in your journey as a software developer. The code examples I share in this post will be in JavaScript but the concepts are common among all languages. What you learn here can easily be translated to any other language you work with.

In this post I’ll be covering how to perform the create, read update and delete operations using arrays, some common functions that come with the Array prototype and also how to implement them.

What is an Array

Before we jump into the juicy bits of Arrays, lets quickly gloss over what they are. Arrays

  • are a fundamental data type in JavaScript
  • are an ordered collection of values called **elements **that are stored at and accessed via an index
  • are untyped, meaning that the elements of an array could be of different types. This allows us to create complex arrays such as an array of objects or even an array of arrays (multidimensional arrays)
  • can have elements that are constants or expressions
  • have a property called length that tells you the number of elements in the array
  • inherit properties from Array.prototype that includes a wide variety useful functions that can be called from arrays or array-like objects

CRUD operations using Arrays

If you’re not familiar with the term CRUD it stands for Create, Read, Update and Delete. In this section we’ll go through each one of these operations and cover different ways you can perform each one.

Creating Arrays

There are several ways you can create an Array but the most common ways are by using

  • the Array literal syntax
  • the Array constructor i.e. new Array()

Lets take a look at each one with examples

Array literal

The array literal is the most common way of creating an array. It uses the square brackets as a notion of a container followed by comma separated values inside the square brackets. The following examples show how to use the array literal syntax and how arrays are untyped i.e. can contain elements of different types.

Image for post

Examples of untyped arrays in JavaScript created with the array literal syntax.

Array constructor

Another way to create an array is through the Array constructor.

const myArray = new Array();

Using the Array constructor, as shown above, is the same as creating an array with the array literal syntax. i.e.

// The following two lines behave exactly the same way i.e. both create an empty arrays

const myArray = new Array();
const myOtherArray = [];

The array constructor, however, is able to receive arguments that allow it to behave in different ways depending on the number and type of arguments passed to it.

  • You can pass a single numeric argument which creates an array of the specified length. This option is mostly used when you know how many elements you’ll be placing in the array
const myArray = new Array(5);

Note: If you want to define the array with a specified size, as shown above, the argument passed must be a numeric value. Any other type would be considered as the first element that’ll be placed in the array.

  • Or you can pass two or more arguments or a non-numeric argument to place the values inside the array. This works the same way as shown in the array literal examples.

Image for post

Examples of arrays created by using the Array constructor in JavaScript

As stated earlier, these two ways are the most common ways of creating arrays that you’ll see and use 99% of the time. There are a few other ways but we won’t dive deep into how they work. They are

  • the spread operator const someArray = […someOtherArray]
  • the static method Array.of()
  • and the static method Array.from()

#javascript #web-development #javascript-tips #javascript-development #javascript-arrays #sql