How to decrease prod bundle size?

Question

I have a simple app, initialized by angular-cli.

It display some pages relative to 3 routes. I have 3 components. On one of this page I use lodash

Answer 1

This did reduce the size in my case:

ng build --prod --build-optimizer --optimization.

For Angular 5+ ng-build --prod does this by default. Size after running this command reduced from 1.7MB to 1.2MB, but not enough for my production purpose.

I work on facebook messenger platform and messenger apps need to be lesser than 1MB to run on messenger platform. Been trying to figure out a solution for effective tree shaking but still no luck.