Using ng-metadata (Angular 1.x Using >= 2 Style)

The ng-metadata approach is done with Angular 1.x dependencies and a few smallhelper libraries. ng-metadata allows developers to use Angular 2 styleTypeScript (annotations/decorators) without Angular 2. Unfortunatelytemplates are still mostly in Angular 1.x style.

Once an application is converted to ng-metadata style it is very close to Angular2, but still requires refactoring. In most cases, ng-metadata is not as efficientas ng-upgrade with respect to refactoring time. The payload of anng-metadata application is smaller, and porting to ng-metadata can be done in aneven more ad-hoc fashion than with ng-upgrade.

The general flow of using ng-metadata with an application is:

• Install ng-metadata dependencies
• Bootstrap root component
• Upgrade components strategically
• Refactor the codebase to Angular 2
  ng-metadata is favored over the deprecated ng-forward.

原文: https://angular-2-training-book.rangle.io/handout/migrate/ng-metadata/