The web-vitals is a library for measuring all the Web Vitals metrics on real users, in a way that accurately matches how they're measured by Chrome and reported to other Google tools (e.g. Chrome User Experience Report, Page Speed Insights, Search Console's Speed Report).
Built from source and copied to third party scripts.
To reinstall or update
git clone https://github.com/GoogleChrome/web-vitals cd web-vitals git checkout tags/<version tag> npm install npm build cd dist cp web-vitals.es5.min <path to pkgsite>/third_party