Chrome DevTools November digest

Deanna Rubin

Chrome DevTools moves fast and we wanted to call your attention to some new functionality and improvements we've introduced to a few components. Namely, we're going to talk about some UI changes, high-resolution JS profiling and new Workspaces features.

  • High-resolution profiling now goes to .1 millisecond precision
  • Toolbars rose to the top of Devtools and Overrides moved to the console drawer
  • Workspaces added several features to support adding/removing/searching files

High-Resolution Profiling

CPU profiling is a pretty useful feature for seeing how efficient your Javascript is. In addition to the traditional profile views, we introduced a Flame Chart this summer, which visually represents a page's Javascript processing over time. It can be used to easily view how deep your call stack is going as well as how long the individual functions take to process.

Until recently, both the traditional Heavy (bottom up) and Tree (top down) representations, as well as the Flame Chart, would only show processes down to 1 millisecond precision. For most applications, this is fine. However, if you are working on something where speed really matters in the UI, like a game -- 1 millisecond resolution may be too chunky to get meaningful results for what is causing your site to be slow or for your UI to seem laggy. To enable High Resolution Profiling (currently Canary only):

  1. Open DevTools Settings.
  2. On the General tab, under Profiler, turn on High resolution CPU profiling.

Here's an example of a Flame Chart seen in normal profiling and with high resolution, where we profile loading the home page:

Flame chart with normal resolution.
Flame chart with high resolution.

With normal profiling resolution, process time always gets rounded up to the next millisecond, so a process that only takes 0.1 milliseconds or less still gets reported as taking 1.0 milliseconds, and other processes might not get shown at all in the call stack.

High-resolution profiling has a large overhead in the Javascript VM, which is why it is turned off by default. While it certainly looks cooler than normal profiling resolution, we recommend only using it if you really need the precision.

Devtools UI Improvements

While there are always new things being rolled out in Canary, we wanted to call your attention to a few major UI changes: Buttons rising to the top of the UI in general, the Timeline navigation and information panels, and the relocation of Overrides to the Console Drawer.

First, let's take a look at where we're coming from. Because we're talking about Timeline anyway, I'll try to kill the first two birds with one pair of screenshots. Here's what Timeline looks like in Chrome (stable) right now:

Old timeline.

And here's what Timeline looks like now.

New timeline.

Notice the following things:

  1. The toolbars and buttons are all at the top of the screen now, both for the specific Timeline ones on the left and the general DevTools ones on the right.
  2. The Timeline records now have their nesting structure in the panel to the left, and you can even use the keyboard to scroll through them. In addition to using up and down keys to scroll up and down, you can also use the left and right keys to open and close nested records.
  3. Time details are now displayed in a panel on the right for whichever entry you've selected. (You can also hover over other entries to get their information.)

Now let's take a look at the console drawer. To open the console drawer, press Escape from within DevTools or hit the console drawer button Drawer Icon and the drawer rolls up from the bottom.

By default, you will have Console and Search tabs there. To get to the functionality formerly known as Overrides, open the DevTools settings and check the box next to "Show 'Emulation' view in console drawer". Close the settings box and you will have an Emulation tab in the console drawer like the screenshot here:

Console drawer and overrides.

And you can do all of your emulation there.

The reason for this change is that before, you would have to go in and out of Settings to change your emulation overrides, and then go back and view your page. Now you can change around your emulation overrides while still manipulating styles.

Improved Workspaces

Workspaces in particular is a feature that can simplify your authoring workflow quite a bit, and yet it doesn't get nearly as much love as it deserves. With Workspaces, rather than experimenting and making changes in DevTools and having to copy and paste your changes back to your source files, you can make changes in DevTools, see them rendered in the browser, and save them to a persistent local version of your files -- all without leaving Chrome.

If you haven't read the Chrome Developer Tools Revolutions 2013 article yet, go ahead and take a look at that and then come back here to learn how we've improved on those features in the last few months.

Adding Files Easier

Back at the time of the Revolutions 2013 article, creating a new workspace required adding the folder to your workspaces and then mapping the folder to a network resource. We've simplified this process to a single step: Simply right-click in the left panel of Sources and select Add Folder to Workspace. This launches you into a file dialog where you can choose a new folder to add to your Workspaces. (It does not add the currently highlighted folder to your Workspaces.)

Add folder to workspace.

Creating and Removing Files

You can add new files to the local directory you're using for Workspaces within Workspaces itself now. Simply right-click on a folder in the left Sources panel and select New File.

New file.

You can also remove files from within Workspaces. Right-click on a file in the left Sources panel and select Delete File.

Remove file.

You can also duplicate a file by selecting Duplicate File.


Now that you can create new files (or delete files) directly in workspaces, the Sources directory will also automatically refresh and show these new files. If not, you can always right-click on a folder and select Refresh from the pop-up menu to force a refresh.

This is also useful if you happen to change your files open in another editor and want the changes to show up in DevTools.

Search Across Files

We've refined the interface for searching across files a little bit, and now you can also search for strings across all of the files in your workspaces as well as all of the files loaded into DevTools. You can either search for a string or for a regular expression, and we match every occurrence in every file or page. To search multiple files in Workspaces (currently in Canary):

  • Open the console drawer by pressing the Escape key, and click the Search tab next to Console to open the Search window


Press Ctrl + Shift + F (Cmd + Opt + F on Mac) to open the Search window.

  • Type your query into the Search Sources box, and hit Enter. If your query is a regular expression or needs to be case-insensitive, click the appropriate box.
Search across files.

Ignore Lists

Searching through the text of files or filtering through filenames can get very tedious if you have a ton of .git files or files cluttering up your results.

Thus, we've added an ignore list feature into Workspaces so you can exclude certain file types or folders when viewing and searching your workspace.

Here's how you can view and change the current shared ignorelist in Workspaces:

  1. Open DevTools Settings.
  2. Click Workspace.
  3. Under Common, within the Folder exclude pattern box, you can view and/or edit the patterns.
Exclude file patterns.

We ship with these default global exclude patterns:

This regex excludes metadata from Git, SVN, Mercurial, project files from Eclipse and IntelliJ, OS X DS_Store and Trash files, and a few other things worth ignoring like cache from Sass. Their entire folder, including any children are excluded from the UI to not show up in the UI and to not show up when searching through files.

Workspace-specific Ignore Lists

To get more specific, you can also choose to exclude files and folders inside your particular workspace to reduce clutter in searches. Excluded folders will not show up in the sources directory either.

To exclude an entire folder from your workspace, right-click on the folder in the left Sources panel and select Exclude Folder. To see the mappings and excluded folders for a given workspace folder:

  1. Open the DevTools Settings.
  2. Click Workspace.
  3. Highlight the folder you're interested in.
  4. Click Edit and the "Edit file system" window appears; you can add or remove mappings and/or excluded folders from this window.
Exclude folders.