I'm new to Angular2 and I don't understand that <> syntax :
example 1 ( from https://angular.io/docs/ts/latest/guide/dependency-injection.html ) :
let mockService = <HeroService> {getHeroes: () => expectedHeroes }
example 2 ( from https://angular.io/docs/ts/latest/guide/template-syntax.html )
deleteRequest = new EventEmitter<Hero>();
Any help or reference to a comprehensive answer is appreciated.
<HeroService> {getHeroes: () => expectedHeroes }
corresponds to a cast / type assertion to the HeroService
class. The returned object will follow the structure of this class.
new EventEmitter<Hero>();
is a way to parametrize the EventEmitter
class (generics) to tell that it'll handle elements of type Hero
. In the case of the EventEmitter
class (see https://github.com/angular/angular/blob/master/modules/%40angular/facade/src/async.ts#L80), it ensures that objects used as a parameter of the emit
method must be of type Hero
.
See the following links for more details:
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