绑定到 angular2 中的组件属性

Question

I'd like to reference a property on a component within A. that' component's constructor B. that component's template. The apis on this seem to be shifting a little bit, but i'd expect the following to work:

<my-component [greeting]="hello"></my-component>

// my component.es6.js
@Component({
  selector: 'my-component',
  properties: {
   'greeting': 'greeting'
  }
})
@View({
  template: '{{greeting}} world!'
})
class App {
  constructor() {
    console.log(this.properties) // just a guess
  }
}

Plunkr

What am I doing wrong?

Answer 1

I was experimenting with Angular2 and came up against the same problem. However, I found the following to work with the current alpha version (2.0.0-alpha.21)

@Component({
  selector: 'hello',
  properties: {'name':'name'}
})
@View({
  template:`<h1>Hello {{_name}}</h1>`
})
class Hello {
  _name: string;

  constructor() { 
    console.log(this);
  };

  set name(name){
    this._name = name;
  }
}

@Component({
  selector: 'app',
})
@View({
  template:
  `
    <div>
      <hello name="Matt"></hello>
    </div>
  `,
  directives: [Hello]
})
class Application {
  constructor() { };
}

bootstrap(Application);

It seems that properties on the Class that is passed to bootstrap are ignored. Unsure if this is intended or a bug.

Edit: I've just built Angular2 from source and tried the @Attribute annotation, it works as per the docs (but only on the nested component).

constructor(@Attribute('name') name:string) { 
    console.log(name);
};

Prints 'Matt' to the console.

Answer 2

The current way is to decorate the property as @Input.

@Component({
    `enter code here`selector: 'bank-account',
    template: `
    Bank Name: {{bankName}}
    Account Id: {{id}}
    `
})
class BankAccount {
    @Input() bankName: string;
    @Input('account-id') id: string;
    // this property is not bound, and won't be automatically updated by Angular
    normalizedBankName: string;
}
@Component({
    selector: 'app',
    template: `
    <bank-account bank-name="RBC" account-id="4747"></bank-account>`,
    directives: [BankAccount]
})
class App {}
bootstrap(App);

above example is from https://angular.io/docs/ts/latest/api/core/Input-var.html

Answer 3

Actually, you can do it better way. When you are defining properties in your component, you always specify it the following way:

howYouReadInClass:howYouDefineInHtml

So, you may as well do the following:

@Component({
  selector: 'my-component',
  properties: {
   'greetingJS:greetingHTML'
  }
})
@View({
  template: '{{greeting}} world!'
})
class App {
set greetingJS(value){
this.greeting = value;
}
  constructor() {

  }
}

This way you will not get conflicts in TS, and you will have a clearer code - you will be able to define the variable as you define it in partent component.