## 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
- `NgHost` to `CompilerHost`
- `AotCompilerHost.resolveFileToImport` to `AotCompilerHost.fileNameToModuleName`
- `AotCompilerHoset.resolveImportToFile` to `AotCompilerHost.moduleNameToFileName`
This is needed to resolve symbols without `.d.ts` files.
This bumps the version of the metadata from 1 to 2.
This adds logic into `ng_host.ts` to automatically upgrade
version 1 to version 2 metadata by adding the exported symbols
from the `.d.ts` file.
Prior to this commit, translations were built in the serializers. This
could not work as a single translation can be used for different source
messages having different placeholder content.
Serializers do not try to replace the placeholders any more.
Placeholders are replaced by the translation bundle and the source
message is given as parameter so that the content of the placeholders is
taken into account.
Also XMB ids are now independent of the expression which is replaced by
a placeholder in the extracted file.
fixes#12512
This improves ergonomics a bit by allowing people to write:
`<label [for]="ctxProp"></label>`.
This is similar to the existing class -> className mapping.
Closes#7516
Previously, if a `TemplateRef` was created in a `ViewContainerRef`
at a different place, the content was not query able at all.
With this change, the content of the template can be queried
as if it was stamped out at the declaration place of the template.
E.g. in the following example, the `QueryList<ChildCmp>` will
be filled once the button is clicked.
```
@Component({
selector: ‘my-comp’,
template: ‘<button #vc (click)=“createView()”></button>’
})
class MyComp {
@ContentChildren(ChildCmp)
children: QueryList<ChildCmp>;
@ContentChildren(TemplateRef)
template: TemplateRef;
@ViewChild(‘vc’, {read: ViewContainerRef})
vc: ViewContainerRef;
createView() {
this.vc.createEmbeddedView(this.template);
}
}
@Component({
template: `
<my-comp>
<template><child-cmp></child-cmp></template>
</my-comp>
`
})
class App {}
```
Closes#12283Closes#12094
Tobias Bosch
Bowen Ni
Chuck Jazdzewski
Alex Eagle
Matias Niemelä
Victor Berchet
Joao Dias
Pawel Kozlowski