IE slow when compiled for prod but not dev or stage


#1

I have an app that is bundled with Webpack. The issue I’m describing happens with Webpack 3 and Webpack 4. I upgraded to 4 hoping it would resolve it, but it didn’t.

When running “au build”, the resulting application runs quickly in IE (not as fast as other browsers, but still usable). When running “au build --env prod” the resulting app takes over a minute to load.

I started removing features until I was down to nothing but a blank screen and it still experiences the issue. I hard-coded webpack.config options until I produced two apps that were the exact same except for one that had embedded maps in the bundles and one which didn’t. The app with the embedded bundles runs fast in IE11 and the one without runs slow.

I can reproduce this by simply scaffolding a new project with the cli using typescript, sass, and Webpack. You end up with the standard Hello World aurelia app. “au build” and then run in IE11. The “Loading…” status shows up for about a second. Then, “au build --env prod” and run in IE. The “loading…” status shows up for 6 - 10 seconds before “Hello World” appears.

The only difference that matters is whether the js map exists in the bundle or not. It runs faster with it there.

Any ideas on how to resolve this?


#2

I know that the bluebird promise polyfill causes issues with IE11. Would you mind exchanging this one for a different implementation, e.g. es6-promise (I use v4.2.4 with IE11).


#3

Aaaaaand, that was it. Thanks @mp24!