Lighthouse 2.6 is out! Highlights include:
- New performance audits.
- A rehaul of the accessibility section score.
- Improvements to the report UX.
- A bug fix for the aspect ratio audit.
See the 2.6 release notes for the full list of new features, changes, and bug fixes.
How to update to 2.6
- NPM. Run
npm update lighthouse
. Runnpm update lighthouse -g
flag if you installed Lighthouse globally. - Chrome Extension. The extension should automatically update, but you can manually update it
via
chrome://extensions
. - DevTools. The Audits panel will be shipping with 2.6 in Chrome 65. You can check what version
of Chrome you're running via
chrome://version
. Chrome updates to a new version about every 6 weeks. You can run the latest Chrome code by downloading Chrome Canary.
New performance audits
JavaScript boot-up time is high
View a breakdown of the time your page spends parsing, compiling, and executing each script. JavaScript boot-up time is a somewhat-hidden but important factor in page load time.
![The 'JavaScript boot-up time is high' audit.](/static/blog/lighthouse-2-6/image/the-javascript-boot-tim-2303d8232cfbf.png)
Uses inefficient cache policy on static assets
Make sure that the browser properly caches each of your resources.
![The 'Uses inefficient cache policy on static assets' audit](/static/blog/lighthouse-2-6/image/the-uses-inefficient-cac-b45e52234b0cb.png)
Avoids page redirects
Page redirects add an extra network roundtrip, or two if an extra DNS lookup is required. Minimize redirects in order to speed up page load time.
![The 'Avoids page redirects' audit](/static/blog/lighthouse-2-6/image/the-avoids-page-redirect-51674b3b322f4.png)
Rehaul of the accessibility section score
In Lighthouse 2.6, the aggregate accessibility score is calculated differently. The score weighs each accessibility audit based on the severity of its impact on user experience, as well as the frequency of the issue, based on the HTTP Archive dataset. See googlechrome/lighthouse/issues/3444 for an in-depth discussion.
Report UX Improvements
Top-level errors
At the top of your report, Lighthouse alerts you to errors that may have affected your page's scores.
![Top-level errors at the top of a report](/static/blog/lighthouse-2-6/image/top-level-errors-the-top-fa815916decad.png)
Print summary and expanded views
Click Export Report then select Print Summary or
Print Expanded to print out summarized or detailed versions of your reports.
![Print summary and expanded views](/static/blog/lighthouse-2-6/image/print-summary-expanded-v-b037203b4b5a7.png)
Aspect ratio bug fix
2.6 also fixes a bug that caused the Displays images with correct aspect ratio audit to fail even when there were no images on the page, or all images were properly sized.