What's New In DevTools (Chrome 72)

New features and major changes coming to Chrome DevTools in Chrome 72 include:

• Visualize performance metrics in the Performance panel.
• Highlight text nodes in the DOM Tree.
• Copy the JS path to a DOM node from the DOM Tree.
• Audits panel updates, including a new audit that detects JS libraries and new keywords for accessing the Audits panel from the Command Menu.

Video version of these release notes #

Visualize performance metrics #

After recording a page load, DevTools now marks performance metrics like DOMContentLoaded and First Meaningful Paint in the Timings section.

Figure 1. First Meaningful Paint in the Timing section

Highlight text nodes #

When you hover over a text node in the DOM Tree, DevTools now highlights that text node in the viewport.

Figure 2. Highlighting a text node

Copy JS path #

Suppose you're writing an automation test that involves clicking a node (using Puppeteer's page.click() function, perhaps) and you want to quickly get a reference to that DOM node. The usual workflow is to go to the Elements panel, right-click the node in the DOM Tree, select Copy > Copy selector, and then pass that CSS selector to document.querySelector(). But if the node is in a Shadow DOM this approach doesn't work because the selector yields a path from within the shadow tree.

To quickly get a reference to a DOM node, right-click the DOM node and select Copy > Copy JS path. DevTools copies to your clipboard a document.querySelector() expression that points to the node. As mentioned above, this is particularly helpful when working with Shadow DOM, but you can use it for any DOM node.

Figure 3. Copy JS path

DevTools copies an expression like the one below to your clipboard:

document.querySelector('#demo1').shadowRoot.querySelector('p:nth-child(2)')

Audits panel updates #

The Audits panel is now running Lighthouse 3.2. Version 3.2 includes a new audit called Detected JavaScript libraries. This audit lists out what JS libraries Lighthouse has detected on the page. You can find this audit in your report under Best Practices > Passed audits.

Figure 4. Detected JavaScript libraries

Also, you can now access the Audits panel from the Command Menu by typing Lighthouse or PWA.

Figure 5. Typing lighthouse into the Command Menu