NgIf syntax has been extended to support else clause to display template
when the condition is false. In addition the condition value can now
be stored in local variable, for later reuse. This is especially useful
when used with the `async` pipe.
Example:
```
<div *ngIf="userObservable | async; else loading; let user">
Hello {{user.last}}, {{user.first}}!
</div>
<template #loading>Waiting...</template>
```
closes#13061closes#13297
## 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
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.
Add support for the `$postDigest()` and `$onDestroy()` lifecycle hooks.
Better align the behavior of the `$onChanges()` and `$onInit()` lifecycle hooks
with Angular 1.x:
- Call `$onInit()` before pre-linking.
- Always instantiate the controller before calling `$onChanges()`.
Add upgrade-static.umd.js bundles
This allows depending on it without getting a transitive dependency on compiler.
BREAKING CHANGE:
Four newly added APIs in 2.2.0-beta:
downgradeComponent, downgradeInjectable, UpgradeComponent, and UpgradeModule
are no longer exported by @angular/upgrade.
Import these from @angular/upgrade/static instead.
Misko Hevery
Victor Berchet
Dzmitry Shylovich
Jónatan Núñez
Alex Rickabaugh
Bowen Ni
Victor Savkin
vsavkin
Tobias Bosch
Pawel Kozlowski
Bowen Ni
Alex Eagle
Chuck Jazdzewski
Peter Bacon Darwin
Matias Niemelä
Joao Dias
João Dias
Georgios Kalpakas
Thomas Shafer
Jeremy Elbourn