Decorated/Computed arrays in Angular2

I have a component, which i want to use like this

<comp [list]="['alpha', 'bravo', 'charlie']"></comp>

i.e, i want it to display the contents of a list.

The compontent's code is

@Component({
    selector: 'comp',
    template: `
      <ul>
        <li *ngFor="item of decoratedList()">
           -  - 
        </li>
      </ul>`
})
class Comp {
    list: any[];

    decoratedList(): any[] {
        return this.list.map(item => ({
          name: item,
          foo: fooIt(item),
          bar: barIt(item)
       }));
    }
} 

The Problem with this code is decoratedList, because it returns a new list every check, due to it's use of map, which leads to decoratedList() has Changed-type errors.

What is an ideomatic way in angular to handle such a pattern?