Angular2 filtering array of objects based on an array of objects using pipe

Question

I'm struggling to get my head around how to filter an array of objects based on another array of objects using the angular pipe. What i have so far is a pipe that filters based on a single argument.

I have 2 arrays, array1 and array 2, which both contain complex objects. The filtered array (array1) should only contain objects where array1.value === array2.value

My code so far:

import { Injectable, Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'arrayFilter'
})
@Injectable()
export class AttributeFilterPipe implements PipeTransform {
  transform(array: any[], filterFrom: any[]): any {
    return array.filter(item => item.value.indexOf(filterFrom[0].value) !== -1);
  }
}

The filtered array (array1) should only contain objects where array1.value === array2.value - comparing objects at the same index? or array1 should only have objects contained in array 2? — tymeJV
– tymeJV, Commented Feb 3, 2017 at 16:48
array1 should only contain objects that are in array2. The comparison should be done on array1[i].value === array2[i].value — Steve Fitzsimons
– Steve Fitzsimons, Commented Feb 3, 2017 at 16:50

Laxmikant Dange · Accepted Answer · 2017-11-23 05:05:57Z

8

If array 1 should only contain objects that are in array 2:

return array.filter(item => filterFrom.some(f => f.value == item.value));

If array 1 should only contain objects that are in array 2 at the same index:

return array.filter((item, index) => item.value == filterFrom[index].value);

edited Nov 23, 2017 at 5:05

Laxmikant Dange

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answered Feb 3, 2017 at 16:49

tymeJV

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3 Comments

Steve Fitzsimons Over a year ago

Option one works but my array has lost its order. Is there any way to filter and keep the order of array1?

Steve Fitzsimons Over a year ago

So I made a mistake and the array (array1) is staying in the correct order. My problem now is I need the order of array1 to be that of array2

cmartin Over a year ago

+1 Almost exactly what I wanted but the opposite. I needed to filter an array and pull out all items not within a second array. That code is: return array.filter(item => !filterFrom.some(f => f.value == item.value));

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