Your plan is called the "big bang rewrite", it's very common, and it's a bad idea.
In most cases, it’s the Big Bang approach that wins the argument.
But by making it a Big Bang release, you’ve maximized the chances that you’ll be behind schedule when you get to the end, and you’ve therefore maximized the chances that you won’t spend enough time preparing. This results in a bad time for both you and your customers.
Unfortunately, perhaps due to something intrinsic in human nature, this scenario is a cliche for Big Rewrite projects.
— Chad Fowler: The Big Bang
One of the keys to a successful upgrade is to do it incrementally, by running the two frameworks side by side in the same application, and porting AngularJS components to Angular one by one. This makes it possible to upgrade even large and complex applications without disrupting other business, because the work can be done collaboratively and spread over a period of time. The upgrade module in Angular has been designed to make incremental upgrading seamless.
For more information, see
- Angular Developer Guide - Upgrading from AngularJS
- Migrating AngularJS to Angular 4,5 (with DEMO)
- Running Angular and AngularJS frameworks side by side
- AngularJS Developer Guide - Component-based application architecture
- AngularJS 1.5+ Components do not support Watchers, what is the work around?
