JavaScript Console log() Tutorial

In this section, we will learn what the console log() method is and how to use it in JavaScript.

Logging in JavaScript

In programming languages like JavaScript, when creating a program, we need to monitor every step and make sure they are running accurately.

One way to run this monitoring is by sending messages from different sections of a program to a place like a file or, in case of JavaScript, to a browser console.

This is called logging.

After sending messages to a browser console, developers can check those logs and analyze to see if the program is working correctly or there are bugs to be fixed, etc.

JavaScript Console log() Method

The `log()` method in JavaScript is a way of sending messages that are considered as log to a browser console.

Console log() Method Syntax:

console.log(message)

Console log() Method Parameter:

The `log()` method takes a variable number of arguments and these are basically the messages (logs) that we want to send to a browser console.

Console log() Method Return Value:

The return value of this method is undefined.

Example: JavaScript print to console

console.log("This is a message coming from the log method.");

const name = "John Doe";

console.log(name);

Output:

This is a message coming from the log method.

John Doe

Example: JavaScript write in console

console.log("This is a message coming from the log method.");

const name = "John Doe";

console.log(name, "Omid Dehghan");

Output:

This is a message coming from the log method.

John Doe Omid Dehghan

Example: JavaScript output to console

const obj = {

name: "John Doe"

}

console.log(obj);

Output:

{name: 'John Doe'}

Here the argument of the `log()` method is an object and as you check the browser console, you’ll see that the message is exactly the content of the object.

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