Monitor Events and Function Calls via Console

By  on  

Despite having worked on the very complex Firefox for a number of years, I'll always love plain old console.log debugging. Logging can provide an audit trail as events happen and text you can share with others. Did you know that chrome provides monitorEvents and monitor so that you can get a log each time an event occurs or function is called?

Monitor Events

Pass an element and a series of events to monitorEvents to get a console log when the event happens:

// Monitor any clicks within the window
monitorEvents(window, 'click')

// Monitor for keyup and keydown events on the body
monitorEvents(document.body, ['keyup', 'keydown'])

You can pass an array of events to listen for multiple events. The logged event represents the same event you'd see if you manually called addEventListener.

Monitor Function Calls

The monitor method allows you to listen for calls on a specific function:

// Define a sample function
function myFn() { }
// Monitor it
monitor(myFn)

// Usage 1: Basic call
myFn()
// function myFn called

// Usage 2: Arguments
myFn(1)
// function myFn called with arguments: 1

I really like that you can view the arguments provided, which is great for inspecting.

I usually opt for logpoints instead of embedding console statements in code, but monitor and monitorEvents provide an alternative to both.

Recent Features

  • By
    CSS 3D Folding Animation

    Google Plus provides loads of inspiration for front-end developers, especially when it comes to the CSS and JavaScript wonders they create. Last year I duplicated their incredible PhotoStack effect with both MooTools and pure CSS; this time I'm going to duplicate...

  • By
    Conquering Impostor Syndrome

    Two years ago I documented my struggles with Imposter Syndrome and the response was immense.  I received messages of support and commiseration from new web developers, veteran engineers, and even persons of all experience levels in other professions.  I've even caught myself reading the post...

Incredible Demos

  • By
    Implement the Google AJAX Search API

    Let's be honest...WordPress' search functionality isn't great. Let's be more honest...no search functionality is better than Google's. Luckily for us, Google provides an awesome method by which we can use their search for our own site: the Google AJAX Search API.

  • By
    Translate Content with the Google Translate API and JavaScript

    Note:  For this tutorial, I'm using version1 of the Google Translate API.  A newer REST-based version is available. In an ideal world, all websites would have a feature that allowed the user to translate a website into their native language (or even more ideally, translation would be...

Discussion

  1. Oh my chickens, this is amazing!! I can’t tell you how many times I’ve tried to poke around in the Chrome dev tools sources and elements tab trying to find way to listen for events. This is going completely change everything!!

  2. Steve

    It needs to be noted that these are not (yet) universal methods, this only works in Chromium based browsers.

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!