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How To Enable Or Disable Console.log For Debugging

So you are working on your Javascript project and you want to know how to enable or disable console.log messages? Then read on to learn how you can do it quite easily.

Whenever you are working with Javascript, be it on the front-end side with vanilla Javascript or frameworks like React, Vuejs etc. Or on the backend with Node JS, Express JS etc for your servers, you want a way to debug the code. Right?

One of the easiest way we try to debug our code is by using simple print statements. So on the Javascript end, this usually boils down to using console.log( ) messages.

But here is the thing. When you use a programming language that will be compiled – such as C, C++ or Java, we can use compiler flags to enable or disable debug messages.

However, for an interpreted language like Javascript, we dont have a built in method for how to Enable or Disable console.log( ) messages.

So what do we do in that case? Well, if we don’t have a built-in method to enable or disable Javascript console.log( ), then we need to create one!

And that is what we are going to do here. We will be writing a simple Javascript module that we can use to enable or disable Javascript’s console.log( ) messages.

So how do we design this piece of code?

Here is what we are going to do. Instead of using console.log( ) to print our debug messages, we will use our own custom function called debugLog( ). But within this debugLog( ) function, we will have a simple Debug Enable (or) Disable flag.

Now when this flag is set, we will call the console.log( ) in turn and if not set, we will skip printing the log messages. It is as simple as that!

Sounds good? Great! So here is the piece of code that does just that!

How to Enable or Disable console.log
How to Enable or Disable console.log using a switch?

Create a file called “utils.js” and add the following piece of code into it:

DEBUG = true;

function debugLog(msg) {
    if (DEBUG) {
        console.log(msg);
    }
}

//For express.js, we need to export this module
module.exports = debugLog;

So that is it! From now on, call debugLog( ) instead of console.log( ) to write your debug message. An example piece of such a debug message is shown below:

debugLog("[app] Connect to mongoDB...");

So whenever you want to switch on the debug logging, set the flag as below:

DEBUG = true;

But the moment you want to turn these debug messages OFF, just set it to false:

DEBUG = false;

And that is all there is to it! This is how you can enable or disable console.log( ) messages for debugging!

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