local-assigner

gistfile1.ts

//@vsavkin did most of the work
//Angular 2 directive to allow setting a local variable from within a template.
//Usage example with an "auth" observable, whose unwrapped value gets set to "unwrapped":
/*
  <span *assign-local="#unwrapped to auth | async">
    <button (click)="login()" *ng-if="!unwrapped">Login</button>
  </span>
*/
import {
  Directive,
  ViewContainerRef,
  ProtoViewRef
} from "angular2/angular2";

@Directive({selector: '[assign-local]', properties: {'localVariable': 'assignLocalTo'}})
class LocalVariable {
  viewContainer: ViewContainerRef;
  protoViewRef: ProtoViewRef;
  view: any;
  constructor(viewContainer: ViewContainerRef, protoViewRef: ProtoViewRef) {
    this.viewContainer = viewContainer;
    this.protoViewRef = protoViewRef;
  }

  set localVariable(exp) {
    if (!this.viewContainer.length) {
      this.view = this.viewContainer.create(this.protoViewRef);
    }

    this.view.setLocal("$implicit", exp);
  }
}