## Inheritance Semantics:
Decorators:
1) list the decorators of the class and its parents in the ancestor first order
2) only use the last decorator of each kind (e.g. @Component / ...)
Constructor parameters:
If a class inherits from a parent class and does not declare
a constructor, it inherits the parent class constructor,
and with it the parameter metadata of that parent class.
Lifecycle hooks:
Follow the normal class inheritance model,
i.e. lifecycle hooks of parent classes will be called
even if the method is not overwritten in the child class.
## Example
E.g. the following is a valid use of inheritance and it will
also inherit all metadata:
```
@Directive({selector: 'someDir'})
class ParentDirective {
constructor(someDep: SomeDep) {}
ngOnInit() {}
}
class ChildDirective extends ParentDirective {}
```
Closes#11606Closes#12892
BREAKING CHANGE:
- all `…Metadata` classes have been removed. Use the corresponding decorator
as constructor or for `instanceof` checks instead.
- Example:
* Before: `new ComponentMetadata(…)`
* After: `new Component(…)`
- Note: `new Component(…)` worked before as well.
BREAKING CHANGE:
Exceptions are no longer part of the public API. We don't expect that anyone should be referring to the Exception types.
ExceptionHandler.call(exception: any, stackTrace?: any, reason?: string): void;
change to:
ErrorHandler.handleError(error: any): void;
Closes#9729
BREAKING CHANGE:
`Type` is now `Type<T>` which means that in most cases you have to
use `Type<any>` in place of `Type`.
We don't expect that any user applications use the `Type` type.
This contains major changes to the compiler, bootstrap of the platforms
and test environment initialization.
Main part of #10043Closes#10164
BREAKING CHANGE:
- Semantics and name of `@AppModule` (now `@NgModule`) changed quite a bit.
This is actually not breaking as `@AppModules` were not part of rc.4.
We will have detailed docs on `@NgModule` separately.
- `coreLoadAndBootstrap` and `coreBootstrap` can't be used any more (without migration support).
Use `bootstrapModule` / `bootstrapModuleFactory` instead.
- All Components listed in routes have to be part of the `declarations` of an NgModule.
Either directly on the bootstrap module / lazy loaded module, or in an NgModule imported by them.
Tobias Bosch
Miško Hevery
Alex Eagle
Victor Berchet