Adding a property to one function, but not all functions, causes Not optimized flag on function containing Function.prototype.apply.
"V8 only recognizes monomorphic .apply call-sites" - @mraleph
See example.js
fix.js)node --trace_opt --trace_deopt example.js | grep "failed to optimize dispatch"
jspm install
http-server # open http://localhost:8080/
xxxxxxxxxx<html lang="en"><head> <meta charset="utf-8"> <title>EventsSpeedTests</title> <style> button { padding: .5em 1em; display: block; text-align: center; margin-top: 5px; width: 200px; } </style></head><body id="home"> <h1>De-opt Test</h1> <script src="jspm_packages/system.js"></script> <script src="config.js"></script> <script> addButton('example'); addButton('example2'); addButton('fix'); function addButton(name) { var element = document.createElement("button"); element.innerHTML = name; element.onclick=function(){ console.log('start',name); var start = new Date().getTime(); System.import('./'+name+'.js').then(function () { var time = new Date().getTime() - start; console.log('end',name, time, 'ms'); }); } document.body.appendChild(element); } </script></body></html>