Thomson Reuters has a lot of code written in AngularJS, and they’ve researched different upgrade paths for AngularJS to Angular migration. They have a GitHub project where they showcase different upgrade paths along with code and explanations. This is an explanation of the different projects:
To summarize, we have a starting project (Fruit1X, for Angular 1.x), that uses older patterns (ControllerAs, Grunt, etc). The rest of the sample projects demonstrate how that application looks after conversion to the target pattern. Fruit15 (for Angular 1.5) shows the Fruit app converted to the AngularJS Component Pattern and implements newer tooling (Webpack, and npm delivery). Fruit20–15 (for Angular/AngularJS 1.5) shows the Hybrid Pattern, with application hosted in an Angular shell via ngUpgrade along with various build and test tools upgraded to modern equivalents. Lastly Fruit20 shows a full Angular rewrite of the project.
The quote above is from the blog post “An Upgrade Path to Angular at Thomson Reuters” from the Angular blog.
If you have AngularJS code that you’re hoping to migrate at some point, then take a look at their GitHub repository.