Stencil custom decorator example

decorator.ts

/*
 * @Component()
 * class ThemedComponent {
 *   @Inject() theme: ITheme;
 * }
 */
 
const theme = {foo: 'bar'};

export function Inject() {
  return (proto: any, prop: string) => {
    const { componentWillLoad } = proto;
    proto.componentWillLoad = function() {
      this[prop] = theme;
      if (componentWillLoad) {
        return componentWillLoad.apply(this);
      }
    };
  };
}