How to go beyond console.log and get the most out of your browser’s debugging console


The console object is a very useful feature of browsers that have been around for many years. It provides access to the browser’s debugging console.
Most web developers know how to print messages to the console using console.log.  But I’ve found that many don’t know about other features of the console, even though they can be very useful for every web developer.

In this post, I’ll go over some of these lesser-known features and capabilities. I hope that you will find them useful and interesting, and will incorporate them into your day-to-day workflow and code.

I added a screenshot of the result of each example. If you want to try things for yourself, just open the DevTools and copy-paste the examples.

Using multiple arguments

It is quite common to log several values together. These may be a message along with a related value or the content of several related variables.

Here are two ways I’ve seen developers achieve this:

1. String concatenation

const a  123;
const b  'abc';
const c  {aa: 234, bb: 345};
console.log('Foo bar ' + a + ' ' + b + ' ' + c);
Result of string concatenation
Result of string concatenation

2. Using multiple calls

const a  123;
const b  'abc';
const c  {aa: 234, bb: 345};
console.log('Foo bar');
Result of multiple calls Result of multiple calls

These methods may work (sort of), but:

  • They are not flexible
  • They are not very readable
  • They are cumbersome to write
  • They need special means to work properly with object variables

There are several better alternatives for outputting many variables. The most useful one for quick data dump is sending multiple arguments to console.log like so:

const a  123;
const b  'abc';
const c  {aa: 234, bb: 345};
console.log('Foo bar', a, b, c);
Result of multiple arguments Result of multiple arguments

This is very handy for debugging, but the output is not very controllable. For output that is intended to be read (like for a library), I would use a different method, which we’ll get to later on.

Using different log levels

Besides the familiar console.log, there are other logging methods that correspond to different log levels:

console.debug('Debug message');'Info message');
console.log('Good old log message');
console.warn('A warning message');
console.error('This is an error');
Log levels as seen in Google Chrome Log levels as seen in Google Chrome

Each log level may have a different default style, which makes spotting errors and warnings at a glance easier.

You can usually also filter which log levels you want to be visible in the DevTools console. This may help reduce clutter.

Filtering log levels in Google Chrome Filtering log levels in Google Chrome

The appearance of the different levels and the filtering granularity changes from browser to browser.

Grouping console lines

Sometimes it is useful to group log messages together. It may allow for more organized and readable output.

This is actually very simple to achieve:;
console.log('First message');
console.log('Second message');
Grouped log messages Grouped log messages

Note that log groups can also be nested and labeled:'Group aaa');
console.log('First message');'Group bbb');
console.log('level 2 message a');
console.log('Level 2 message b');
console.log('Second message');
Nested and labeled groups Nested and labeled groups

In case you want the group to appear collapsed, use console.groupCollapsed()

Measuring performance

Measuring the time between points in the code can serve as a quick way to check the performance of some operations.

Here is a trivial way to do this:

const start;
// do some stuff
console.log('Took ' + ( - start) + ' millis');

This works, but there’s a more elegant way to achieve something similar:

console.time('Label 1');
// do some stuff
console.timeEnd('Label 1');
Measuring time with the console Measuring time with the console

The code is shorter, the measurement is more accurate, and you can keep track of up to 10,000 different timers in parallel on a page.

String substitution

Previously we learned that you can pass multiple arguments to console.log to output multiple values simultaneously. Another way to achieve something similar is to use string substitution. This method requires familiarity with the available placeholders but offers greater control over the output.

const a  123;
const b  'abc';
const c  {aa: 234, bb: 345};
console.log('number %d string %s object %o', a, b, c);
Logging with string substitution
Logging with string substitution

Take a look at the documentation (link at the end) for a list of available placeholders.


It can be nice to style different log messages differently to increase readability.

We already mentioned that browsers give different default styling to some log levels, but this can also be customized according to your specific needs. Styling is done using a subset of CSS rules, passed in a string as the second parameter, and applied using the marker %c.

Note that you can have different styles for different parts of the log message.

For example:

console.log("Normal %cStyled %clorem %cipsum", "color: blue; font-weight: bold", "color: red", "background-image: linear-gradient(red, blue); color: white; padding: 5px;");
Styled log messages Styled log messages


In this post, we have seen some of the features of the console that I think are less well-known and more useful. This is by no means an exhaustive list of everything the console can do, as it has many more tricks up its sleeve.

If this got you interested and you want to find out what other things you can do with the console, I recommend reading the relevant documentation on MDN and trying things out in DevTools.

Subscribe for Email Updates:



ART Success
Agile Contracts Best Practices
Reading List
Change Management
Sprint Iteration
Agile Marketing
Scrum Master
Lean Agile Management
speed @ scale
Risk Management in Kanban
Achieve Business Agility
Agile Development
Coaching Agile Teams
Agile Israel Events
Continuous Improvement
Process Improvement
Releases Using Lean
AI Artificial Intelligence
Professional Scrum Master
Agile Outsourcing
Sprint Planning
Continuous Integration
Operational Value Stream
Scrum Values
IT Operations
Lean-Agile Software Development
Scaled Agile Framework
System Integration Environments
speed at scale
Story Slicing
Lean Software Development
lean agile change management
Jira admin
Certified SAFe
An Appreciative Retrospective
Acceptance Test-Driven Development
Entrepreneurial Operating System®
Scrum With Kanban
Value Streams
Agile Project Management
Kanban 101
Release Train Engineer
Nexus and Kanban
Scrum Master Role
Nexus vs SAFe
Legacy Enterprise
Implementing SAFe
Rapid RTC
Lean Agile
Hybrid Work
Nexus and SAFe
Daily Scrum
Software Development Estimation
Built-In Quality
Kaizen Workshop
Lean and Agile Principles and Practices
Sprint Retrospectives
Iterative Incremental Development
Professional Scrum Product Owner
Kanban Kickstart Example
Risk Management on Agile Projects
Scrum Guide
Manage Budget Creation
What Is Kanban
Introduction to ATDD
Introduction to Test Driven Development
System Team
Business Agility
Legacy Code
Agile Techniques
Limiting Work in Progress
Agile Games
Scrum and XP
Artificial Intelligence
Agile Israel
Lean Agile Organization
Lean Agile Leadership
Agile and DevOps Journey
Implementation of Lean and Agile
Agile for Embedded Systems
Lean-Agile Budgeting
Test Driven Development
Lean Risk Management
Agile Testing Practices
System Archetypes
ScrumMaster Tales
Agile India
Agile Product Development
Lean Agile Basics
Product Ownership
Agile in the Enterprise
PI Planning
Enterprise DevOps
Advanced Roadmaps
Managing Risk on Agile Projects
The Kanban Method
Engineering Practices
PI Objectives
Principles of Lean-Agile Leadership
Agile Basics
Jira Cloud
A Kanban System for Software Engineering
Kanban Basics
Lean and Agile Techniques
Pomodoro Technique
Games and Exercises
Continuous Planning
Agile Program
The Agile Coach
Quality Assurance
Effective Agile Retrospectives
Kanban Game
Development Value Streams
Large Scale Scrum
Jira Plans
Risk-aware Product Development
Agile Risk Management
Agile Exercises
Program Increment
ALM Tools
Agile Assembly Architecture
Portfolio for Jira
Product Management
Nexus Integration Team
Professional Scrum with Kanban
Software Development
Agile Release Planning
Lean Budgeting
Agile Games and Exercises
Elastic Leadership
Agile Release Management
Accelerate Value Delivery At Scale
Lean Startup
RTE Role
Systems Thinking
SAFe DevOps
Agile Delivery
Agile Project
Managing Projects
Applying Agile Methodology
Agile Mindset
Continuous Deployment
Perfection Game
Agile Community
Scrum Primer
Continuous Delivery
SAFe Release Planning
Enable registration in settings - general

Contact Us

Request for additional information and prices

AgileSparks Newsletter

Subscribe to our newsletter, and stay updated on the latest Agile news and events

This website uses Cookies to provide a better experience
Shopping cart