Closed
Description
It would be nice if TS could be more IoC friendly. One of the main pains I have with it, is that it doesn't know an alternative constructor:
import { Component } from '@angular/component';
@Component({})
export class MyComponent {
private a: string; // Error it is never initialized.
ngOnInit() {
this.a = 1
}
}Here we annotate a secondary constructor on IComponent:
interface IComponent {
constructor ngOnInit?();
}And then we instructs the class to implement it, note the use of implements keyword:
function Component(options: any) {
return function<T extends Function>(_class: T implements IComponent): void {
/*...*/
}
}And then, all people can be happy:
@Component({})
export class MyComponent {
private a: string; // No error
ngOnInit() {
this.a = 1
}
}For property decorators, we currently face this problem:
@Component({})
export class MyComponent {
@Input() a: string; // Error no init.
}Here we introduce the initializes keyword:
function Component(options: any) {
return function<T extends Function>(_class: T implements IComponent initializes @Input): void {
/*...*/
}
}Other frameworks are built the other way around, instead of another disjoint function or class providing the construction of the class, a base class provides it. So we could theoretically write our component like below(if we disregard the class annotations ):
export class MyComponent extends BaseComponent {
@Input() a: string;
private b: string;
ngOnInit() {
this.b = '';
}
}And we should be able to achieve the same thing using a base class:
export class BaseComponent initializes @Input {
constructor ngOnInit?(): void
}