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 @supports

    Feature detection via JavaScript is a client side best practice and for all the right reasons, but unfortunately that same functionality hasn't been available within CSS.  What we end up doing is repeating the same properties multiple times with each browser prefix.  Yuck.  Another thing we...

  • By
    6 Things You Didn’t Know About Firefox OS

    Firefox OS is all over the tech news and for good reason:  Mozilla's finally given web developers the platform that they need to create apps the way they've been creating them for years -- with CSS, HTML, and JavaScript.  Firefox OS has been rapidly improving...

Incredible Demos

  • By
    MooTools Window Object Dumping

    Ever want to see all of the information stored within the window property of your browser? Here's your chance. The XHTML We need a wrapper DIV that we'll consider a console. The CSS I like making this look like a command-line console. The MooTools JavaScript Depending on what you have loaded...

  • By
    Spatial Navigation

    Spatial navigation is the ability to navigate to focusable elements based on their position in a given space.  Spatial navigation is a must when your site or app must respond to arrow keys, a perfect example being a television with directional pad remote.  Firefox OS TV apps are simply...

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!!

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