Performance Observer example

performance-observer.js

var observer = new PerformanceObserver(function(list) {
  var perfEntries = list.getEntries();
  for (var i = 0; i < perfEntries.length; i++) {
     // Process entries
     // report back for analytics and monitoring
     // ...
  }
});

// register observer for long task notifications
observer.observe({entryTypes: ["paint"]});