Why is this Angular 2 Pipe not returning data?

Question

I am building an Angular 2 pipe using Angular 2.0.0-RC.4. It should filter all Foo objects passed in as an array of Foo based on property bar. When I step through the code in the debugger, the 'allFoo' var is populated, as is the 'bar' var. I can breakpoint and run the foos.filter() code in the console and it returns an array that I would expect. When I let the function finish, it returns nothing.

Is there a problem with my code or maybe a bug in Angular 2 RC4?

Here is the TypeScript:

import { Pipe, PipeTransform } from '@angular/core';
import { Foo } from '../foo';

@Pipe({
    name: 'barFilterPipe'
})

export class BarFilterPipe implements PipeTransform {
    transform(allFoo: Foo[], bar: string) {
        console.log(allFoo); //data appears correctly here
        console.debug(bar); //and correctly here
        if (allFoo) {
            if (bar == "" || bar == undefined) {
                return allFoo; //if user clears filter
            } else {
                let results: Foo[] = allFoo.filter(afoo => {
                    afoo.bars.indexOf(bar) !== -1; //breakpoint here and type this into console, it returns proper data
                });
                console.log(results); //nothing is returned here
                return results; // or here
            } 
        }
    }
}

For reference, each Foo object looks like this, where the bars property will have varying strings in its array:

{property1: -1, property2: "string", bars: ["A","B","C"]}

Here is the template file where the filter is applied:

<select [(ngModel)]="barFilter" class="form-control">
    <option *ngFor="let bar of barList" [value]="bar">{{bar}}</option>
</select>    
<table class="table">
            <thead>
                <tr>
                    <th>Property1 Name </th>
                    <th>Property2 Name</th>
                    <th>Bars</th>
                </tr>
            </thead>
            <tbody>
                <tr *ngFor="let item of Foos | barFilterPipe : barFilter" [foofoo]="item"></tr>
            </tbody>
        </table>

Here is the Angular class that loads that template and uses the filter:

import {Component, OnInit} from '@angular/core';
import {Foo} from '../foo';
import { BarFilterPipe } from '../Pipes/BarFilterPipe';

@Component({
    selector: 'my-component',
    templateUrl: '../components/myComponent.html',
    directives: [foofoo],
    pipes: [BarFilterPipe]
})
export class MyComponent implements OnInit {
    private barFilter: string;
    private barList: string[];
    private Foos: Foo[] = [{property1: -1, property2: "a", bars: ["A"]}, {property1: -1, property2: "z", bars: ["A","D"]}];
    constructor(){}
    ngOnInit(){
        this.barList = ["","A","B","C","D","E"];
    }
}

Here is the Foo template and class:

<td>
    <h2>{{thisFoo.property1}}</h2>
</td>
<td>
    {{thisFoo.property2}} &nbsp;
</td>
<td>
    <label *ngFor="let bar of thisFoo.bars">{{bar}} &nbsp;</label>
</td>

import {Component, Input} from '@angular/core';
import {Foo} from './foo';

@Component({
    selector: '[foofoo]',
    templateUrl: '../components/foofooComponent.html',
})

export class EstabSummary {
    @Input('foofoo') thisFoo;

}

If I breakpoint at the console.log(results); line, I can type the following on console and it outputs the appropriate data:

let results = allFoo.filter(afoo => {afoo.bars.indexOf(bar);})

I can post the transpiled JS if that will help solve this.

Thanks!

Answer 1

Your filter function doesn't return a boolean value to include array elements. I suspect it should be: return afoo.bars.indexOf(bar) !== -1;

As it is now, every element is excluded.