I was wondering any reasons the RollupJs is chosen over the Webpack 2 given Angular CLI is also using Webpack 2?
Performance and treeshaking
Webpack 2 also supports treeshaking.
Not sure what do you mean “Performance”?
Ive read somewhere, they made the decision right after they saw the time comparison between the two… not sure what kind of time… if im not mistaken, compilation time… something like 8 times gain in speed for rollup compare to webpack…
its in the comment… copied here for convenient
We moved away from gulp because it is effectively deprecated. Installing gulp comes with loads of warnings today, and the tool has not seen a lot of maintenance over the past year. You’re free to use it and roll your own build, or even call our build scripts.
I won’t speak for the Angular team but we settled on Rollup over Webpack because in our testing we saw apps start up in about 350ms with Rollup and 1150 with Webpack. Nolan Lawson did a great post on it here:
As for the breaking changes, there may be a few small ones but the big ones are out of the way.
See conversation on this issue https://github.com/driftyco/ionic-app-scripts/issues/16#issuecomment-250946488, it basically webpack vs rollupjs after that comment.