Angular 6: i18n: How to update an existing .xlf file that has already been translated?

Question

In Angular 6, now that I think I comprehend how to make the i18n files and utilize them (e.g. https://angular.io/guide/i18n), I am wondering about maintenance of said files. If

Answer 1

I ended up making a solution for myself until something better comes along: https://github.com/maplion/angular6-i18n-helpers

So far, it is working pretty well for me.