Brian Grinstead

I have been working on a small collection of snippets that are handy to reuse inside of browser devtools. These can be used in any devtools. You can jump straight to the devtools snippets project page and readme if you want to see some screenshots and details about each individual snippet.

The actual snippets can be seen here: https://github.com/bgrins/devtools-snippets/tree/master/snippets

Why would you use snippets

A common usage for snippets is to replace developer bookmarklet type of functionality. The problem with bookmarklets is that they are a pain to create and share, and even using them can be difficult. You may need to show a bookmarks bar in the UI, run it, and open up devtools to see if it worked. Then you would need to make changes to a giant single line of JavaScript inside of a bookmark manager, or use a generator to convert a .js file into a bookmarklet. Snippets are a much better way to handle this workflow. Examples of this type of snippet would be adding jQuery to a page without it or printing the HTTP headers from the current page.

Another use would be saving console commands that you use during development. For example, if you wrote something to help export information from a page, or print out some debugging data for your application, you can use the multiline snippet editing interface rather than typing in the console. Plus you can save it when you are done in case you need it later.

Browser Support

Firefox has multiline support using the scratchpad editor, and Chrome has a new ‘snippets’ feature.

Currently, in Chrome you have to enable snippets support in chrome://flags and inside of devtools settings (see full instructions and screenshots). They are enabled by default in Canary, so this feature set will soon be widely available. Read more about snippets on the Chrome developer tools documentation.

Firefox Scratchpad is really cool for experimenting with code. In addition to being able to run an entire snippet, you can select just a portion of the code and execute it. Read more about scratchpad on the Firefox developer tools documentation. One thing I would like to see is better management of snippets (‘scratches’?). For example, see the UI for snippet editing in Chrome:

Future Functionality

Things that would be awesome to add:

• Firefox: Better management of snippets. As seen in the screenshot above, it can be really handy to have a UI for storing, editing, and saving changes to the snippets. To be fair, right now you can save scratchpad contents to a file and then ‘open’ or ‘open recent’ later. Maybe if this was pulled more prominently into the UI without needing to open up a file explorer that be enough. It is cool that it actually saves the files to a known place on your disk.
• Chrome: Keyboard shortcut to run a snippet (or part of a snippet). Scratchpad uses Cmd+R/Ctrl+R, which makes sense but may be reserved for reloading the page. Also, storing the snippets in a known place on the disk is really handy, as they could be backed up, copied directly into a project, etc.
• All devtools: Import / export snippets. You can then sync your snippets across computers or share them with others. Maybe some sort of zip or JSON file containing the contents of all the snippets. Or a maybe a URL importer that loads the response into a new snippet, named the path of the request by default. For example, pasting https://raw.github.com/bgrins/devtools-snippets/master/snippets/performance.js would create a new snippet called performance.js with the contents of that request. Then you could just load up the importer with a list of URLs:

https://raw.github.com/bgrins/devtools-snippets/master/snippets/performance.js
https://raw.github.com/bgrins/devtools-snippets/master/snippets/log.js
https://raw.github.com/bgrins/devtools-snippets/master/snippets/base64.js
...

Snippets inside of devtools are big timesavers and are going to be really helpful for a lot of developers. You should check them out if you haven’t yet. Going forward, I’m hoping there will be an easy way to use, manage, and discover new snippets that work across browsers.

I have often found it tricky to get a ‘just-right’ console.log wrapper in JavaScript. I would prefer to just type log, but writing a wrapper function is a little trickier than at first glance. A variation of this used to exist in the HTML5 Boilerplate plugin.js but is now missing.

I have two versions - one is bigger, and is intended for an application - it stubs out console methods when they don’t exist, and exposes a log function to the window. The second is portable - it is meant for use inside of plugins.

The neat thing about this technique is that this preserves the original line of code inside of the console.log statement, rather than the line in which the log function is declared.

The code is in a gist.

I’m still trying to figure out how to get a list of all the colors in use on a page from within devtools, but I’ve been hacking together a little demo with a custom Web Inspector frontend that loads a color palette on the side.

When you click one of the swatches, it sets the current color of the element. The idea is that it would include all the colors in your page, maybe ordered by most used. Possibly could even get more advanced and suggest a set of complementary or analagous colors based on your current selection.

A prototype implementation of a palette using color swatches within devtools

jsbin has made having to remember some of these links less important. However, with jQuery UI 1.9 coming out, there are some CDN links that aren’t working. Here is the updated boilerplate I use to quickly test out a jQuery UI project. If all goes well, you should have a dialog that you can drag around and resize.

<!doctype html>
<html>
<head>
  <title></title>

  <link rel="stylesheet" href="http://code.jquery.com/ui/1.9.0/themes/base/jquery-ui.css">

  <script type="text/javascript" src="http://code.jquery.com/jquery-1.8.2.js"></script>
  <script src="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.9.0/jquery-ui.js" type="text/javascript"></script>

  <style type="text/css">
    #modal {
   background: orange;
    }
  </style>

  <script type='text/javascript'>
    $(function() {
        $("#modal").dialog({ title: "It works" })
    });
  </script>
</head>

<body>
<div id='modal'>jQuery UI!</div>
</body>

</html>

As a bonus, here is the markup in jsbin.

Sometimes I just want to see all (or many) of the variables inside of the function, and it can be a bit of work to copy all of the variables into the console.log() call when you know that you are just going to delete the line afterwards anyway.

It would be great to have a console function that handles this. It would be called console.scope. When you call console.scope() it would act similarly to console.trace(), except instead of seeing the call stack in the console, you would see the same thing that you see in the ‘Scope Variables’ panel when inside a breakpoint in the Sources Panel (see images).

I have also opened a thread about this on the devtools mailing list.