feat request: use uglify-es

[NoNameProvided]

Short description of the problem:

ionic-app-scripts currently use uglify-js to minify Ionic apps. Uglify-js supports only es5 so the typescript compiler must target es5 which leads to more generated code. Using uglify-es would allow to target es6 in tsconfig, so typescript just could leave es6 code untouched instead of compiling it down to es5. This would lead to smaller bundles which would lead to faster startup time.

What behavior are you expecting?

Use uglify-es to minify ionic apps.

Steps to reproduce: n/a

Which @ionic/app-scripts version are you using? 1.3.7

Other information: n/a

[fathyb]

It would gives performances improvements too, when using generators or async/await for example.

[osamasoliman]

related https://forum.ionicframework.com/t/error-occurred-during-command-execution-from-a-cli-plugin/92686

[shyamal890]

+1

[adamduren]

It appears this is already the case in master.