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Console.log(): The Developer’s Swiss Army Knife 

Alexandru Hutanu
Alexandru Hutanu
Engineering Manager

As developers, we rely on console.log() like it’s a third arm. Need to check a value? Console.log. Verify functionality? Console.log. Confused about something? Console.log. It’s our trusty debugging companion.

But console.log() is so much more than a simple print statement. It’s a versatile tool with many capabilities that can seriously level up your debugging game.


My BFF console.log(‘a’)

I’ll admit, my most overused console.log is just logging the letter ‘a’. Nothing fancy, just a simple sanity check that my code is running. I probably log ‘a’ a hundred times a day. It’s my simple little debug routine.

I can’t be alone here! What’s your most used console.log? Share in the comments below. I bet we all have our debugging comfort foods.


console.log() Superpowers

While simply printing values is helpful, did you know console.log can do so much more? Here are some of my favorite tricks:

  • Log styled and colorized output with %c formatting
  • Print stack traces to see where your code is running with console.trace()
  • Time operations with console.time() to find performance issues
  • Organize output into collapsible groups using console.group()
  • Build interactive lists and tables for objects and arrays
  • Generate assertions with console.assert() to validate assumptions

And [many more]! The console API is enormously powerful. It pays to level up your console.log skills.

console.log() update


Better Debugging Alternatives

As great as console.log is, it isn’t a perfect debugging solution. Some downsides:

  • It can clutter your console output
  • Logs may persist in production environments
  • Large volumes of logging can hurt performance
  • Information lacks structure for analyzing trends

For large scale and complex debugging, specialized logging libraries can help. Options like [Winston], [Pino], and [Log4JS] provide much more control over your logging.

Structured logging formats like JSON transform your data into queryable objects. And tools like [LogRocket] give you replayable session recordings to see bugs in action.

So while console.log() may be your first debugging love, it pays to look at other options. Your future self maintaining a complex system will thank you!

console.log() Forever!

Even with fancy debugging tools, console.log() will always have a warm spot in my heart. It’s like an old friend that’s always there to help me out. I don’t think I’ll ever give up my beloved console.log(‘a’)!

How about you? Share your console.log() stories and pro tips! Let’s geek out over everyone’s favorite debugging buddy.

The Humble Beginnings of console.log()

console.log() is the bread and butter of JavaScript debugging. It’s a simple yet powerful tool that allows developers to print messages or data in the browser console. But did you know there’s more to the console than just console.log()? Let’s explore some of its lesser-known siblings and their use cases.

Beyond console.log(): Siblings


  1. console.info(): Similar to console.log()
    , but recommended for printing information required for debugging purposes. In Firefox, a small “i” icon is displayed next to these items in the Web console’s log
  2. console.warn(): Displays a warning message in the console, styled differently to grab your attention. In Chrome and Firefox, warnings have a small exclamation point icon next to them in the Web console log
  3. console.error(): Logs error messages, which are also styled differently to stand out. This method is useful for logging errors and exceptions in your code
  4. console.group() and console.groupEnd(): Groups related log messages together, making it easier to navigate through logs. This is particularly helpful when you have multiple log statements in a function or a complex codebase
  5. console.table(): Prints an array or object in a tabular format, making it easier to read and analyze data. This method is useful when you need to visualize complex data structures or compare multiple objects
  6. console.time() and console.timeEnd(): Measures the time taken to complete a task, useful for performance debugging. This can help you identify bottlenecks in your code and optimize it for better performance
  7. console.trace(): Logs a stack trace, helping you identify the source of an issue. This method is helpful when you need to find the origin of an error or trace the execution flow of your code
  8. debugger keyword: Pauses the execution of your code and opens the browser’s debugging tools, allowing you to step through your code and inspect variables

Advanced console.log() Techniques

In addition to the alternatives mentioned above, there are some advanced techniques you can use with console.log() to improve your debugging experience:

  • String substitution: You can use placeholders like%s,%d, or %f in your log message and pass the corresponding values as additional arguments. This allows you to format your log messages more effectively
  • Styling console text: Apply styles to console text by defining style blocks starting with %c. This can make your log messages more visually appealing and easier to read
  • 8-bit style graphics: Explore the 8-bit fun with console.log() by logging low-fi 8-bit style graphics. This can add a touch of nostalgia and amusement to your debugging sessions

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