Internet Explorer (10, 11) loads the Angular 2 application very slowly

Question

My application runs thanks to Angular 2 and works great in all browsers. However, on IE it is pretty slow to load (10 and 11, I do not support below). For example, when Safari, Chrome, and Firefox require ~ 1.5 s to load, IE takes more than 5 seconds (and 10 seconds on Edge). I looked at the network tab and found that sometimes there is a gap between two calls (from 0.5 to 1 s):

Any idea what could delay IE between two calls?

The only thing I can do is arrange the gaskets in my index.html:

<meta charset="utf-8"> <meta name="viewport" content="width=device-width"> <title>AGA Front App</title> <script src='@routes.Assets.versioned("lib/angular2/es6/dev/src/testing/shims_for_IE.js")'></script> <script src='@routes.Assets.versioned("lib/es6-shim/es6-shim.min.js")'></script> <script src='@routes.Assets.versioned("lib/systemjs/dist/system.src.js")'></script> <script src='@routes.Assets.versioned("lib/typescript/lib/typescript.js")'></script> <script src='@routes.Assets.versioned("lib/angular2/bundles/angular2-polyfills.js")'></script> <script src='@routes.Assets.versioned("lib/rxjs/bundles/Rx.js")'></script> <script src='@routes.Assets.versioned("lib/angular2/bundles/angular2.js")'></script> <script src='@routes.Assets.versioned("lib/angular2/bundles/http.js")'></script> <script src='@routes.Assets.versioned("lib/angular2/bundles/router.dev.js")'></script> <script src='@routes.Assets.versioned("systemjs.config.js")'></script> <script> System.import(path + '/assets/app/bootstrap.ts') .catch(console.error.bind(console)); </script> 

Answer 1

A few thoughts:

• One way to achieve fewer HTTP calls. (combine all source code into one collapsed JS file)
• As you rightly said, your gaskets can also take effect, which can cause a delay. Try using modernizr instead of a few gaskets.

See also:

YUI best practices - https://developer.yahoo.com/performance/rules.html

Launch the app using Google’s performance rules: https://developers.google.com/web/fundamentals/performance/?hl=en