ng2-pipes/src/app/pipes/array/pluck.spec.ts

Useful angular2 pipes

import {PluckPipe} from './pluck';

describe('PluckPipe', () => {
  let pipe: PluckPipe;

  beforeEach(() => {
    pipe = new PluckPipe();
  });

  it('should not change anything if not array', () => {
    expect(pipe.transform('foo', '')).toEqual('foo');
    expect(pipe.transform(null, '')).toEqual(null);
    expect(pipe.transform(undefined, '')).toEqual(undefined);
    expect(pipe.transform(42, '')).toEqual(42);
    expect(pipe.transform({foo: 1, bar: 2}, '')).toEqual({foo: 1, bar: 2});
  });

  it('should return only the properties of the array of object', () => {
    const arr = [{foo: 'bar', a: 1, b: {c: 4}},{foo: 'bar2', a: 2, b: {c: 5}}, {foo: 'bar3', a: 3, b: {c: 6}}];
    expect(pipe.transform(arr, 'a')).toEqual([1, 2, 3]);
    expect(pipe.transform(arr, 'foo')).toEqual(['bar', 'bar2', 'bar3']);
    expect(pipe.transform(arr, 'foo.d')).toEqual([undefined, undefined, undefined]);
    expect(pipe.transform(arr, 'b.c')).toEqual([4, 5, 6]);
    expect(pipe.transform(arr, 'b.c.')).toEqual([undefined, undefined, undefined]);
  });
});