How to sum specific values while filtering the list using filter pipe

I have list of objects (invoices) that have few fields in it. Name, date, description and amountPreTax and amountNet.

In view above the table with all invoices I have fields to filter the list. Search by term, set date 'date to' set date 'date from'.

Under that table I have visible sum of amountPreTax and sum amountNet of all visible invoices.

After I'll filter the list putting some text into search filed or setting 'date to' or 'date from' and list is getting shorter, I want fields of sum updated, so they are sum of only visible invoices.

As far as I know, I need to create one filter for filtering invoices and another for calculating the sum - but I don't know how to write that down and if it's right way to do :)

..

Ok, so far these are my filters (I know, I need to join them as one):

For search term:

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

@Pipe({
    name: 'invoicesFilter',
    pure: false
})
@Injectable()
export class FilterInvoices implements PipeTransform {
    transform(invoices: any[], term: any): any {
        if (invoices && term !== undefined) {
            return invoices.filter((invoice) => {
                return (
                    invoice.number.toLowerCase().indexOf(term.toLowerCase()) !== -1 ||
                    invoice.company.toLowerCase().indexOf(term.toLowerCase()) !== -1 ||
                    invoice.data.toLowerCase().indexOf(term.toLowerCase()) !== -1
                );
            });
        }
        return invoices;
    }
}

For 'date from':

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

@Pipe({
    name: 'dateFrom',
    pure: false
})
@Injectable()
export class FilterDatesFrom implements PipeTransform {
    transform(invoices: any[], date1: any, whichDates: number): any {
        var isDate1 = /(0[1-9]|[12][0-9]|3[01])\.(0[1-9]|1[012])\.(19|20)\d\d/.test(date1);
        if (invoices && isDate1) {
            date1 = date1 + '';
            date1 = date1.split('.');
            date1[0]=parseInt(date1[0]);
            date1[1]=parseInt(date1[1]);
            date1[2]=parseInt(date1[2]);
            return invoices.filter((invoice) => {
                var passDate1 = false;
                var passDate2 = false;
                var date3 = invoice.data;
                var date4 = invoice.datePost;
                date3 = date3.split('.');
                date3[0] = parseInt(date3[0]);
                date3[1] = parseInt(date3[1]);
                date3[2] = parseInt(date3[2]);
                date4 = date4.split('.');
                date4[0] = parseInt(date4[0]);
                date4[1] = parseInt(date4[1]);
                date4[2] = parseInt(date4[2]);
                if(whichDates == 2 || whichDates == 0){
                    if(date1[2]<date4[2]){
                        return invoice;
                    }
                    else if(date1[2]==date4[2])
                    {
                        if(date1[1]<date4[1])
                        {
                            return invoice;
                        }
                        else if(date1[1]==date4[1])
                        {
                            if(date1[0]<=date4[0]){
                                return invoice;
                            }
                        }
                    }
                }
                else if(whichDates == 1 || whichDates == 0){
                    if(date1[2]<date3[2]){
                        return invoice;
                    }
                    else if(date1[2]==date3[2])
                    {
                        if(date1[1]<date3[1])
                        {
                            return invoice;
                        }
                        else if(date1[1]==date3[1])
                        {
                            if(date1[0]<=date3[0]){
                                return invoice;
                            }
                        }
                    }
                }
            });
        }
        return invoices;
    }
}

And 'dates to'

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

@Pipe({
    name: 'dateTo',
    pure: false
})
@Injectable()
export class FilterDatesTo implements PipeTransform {
    transform(invoices: any[], date1: any, whichDates: any): any {
        var isDate1 = /(0[1-9]|[12][0-9]|3[01])\.(0[1-9]|1[012])\.(19|20)\d\d/.test(date1);
        if (invoices && isDate1) {
            date1 = date1 + '';
            date1 = date1.split('.');
            date1[0]=parseInt(date1[0]);
            date1[1]=parseInt(date1[1]);
            date1[2]=parseInt(date1[2]);
            return invoices.filter((invoice) => {
                var passDate1 = false;
                var passDate2 = false;
                var date3 = invoice.data;
                var date4 = invoice.datePost;
                date3 = date3.split('.');
                date3[0] = parseInt(date3[0]);
                date3[1] = parseInt(date3[1]);
                date3[2] = parseInt(date3[2]);
                date4 = date4.split('.');
                date4[0] = parseInt(date4[0]);
                date4[1] = parseInt(date4[1]);
                date4[2] = parseInt(date4[2]);
                if(whichDates == 2 || whichDates == 0){
                    if(date1[2]>date4[2]){
                        return invoice;
                    }
                    else if(date1[2]==date4[2])
                    {
                        if(date1[1]>date4[1])
                        {
                            return invoice;
                        }
                        else if(date1[1]==date4[1])
                        {
                            if(date1[0]>=date4[0]){
                                return invoice;
                            }
                        }
                    }
                }
                if(whichDates == 1 || whichDates == 0){
                    if(date1[2]>date3[2]){
                        return invoice;
                    }
                    else if(date1[2]==date3[2])
                    {
                        if(date1[1]>date3[1])
                        {
                            return invoice;
                        }
                        else if(date1[1]==date3[1])
                        {
                            if(date1[0]>=date3[0]){
                                return invoice;
                            }
                        }
                    }
                }
            });
        }
        return invoices;
    }
}

This is typical object (invoice) structure:

{
    "_id": {
        "$oid": "588b2f345c5948001162fc15"
    },
    "number": "FV/004/12/16",
    "data": "12.12.2016",
    "datePost": "27.01.2017",
    "amountPreTax": 5347.43,
    "amountNet": 4347.5,
    "company": "Stacato Introligatorstwo Małgorzata Tomaszewska",
    "hasTax": "false",
    "orderId": "588a060ebe646d0011df997e",
    "orderNum": "00003",
    "clientNum": "010",
    "clientName": "Eurocasha",
    "isRevenue": false,
    "paid": true,
    "created": "2017-01-27T11:29:50.864Z",
    "file": null
}

And I need to do two sums: "amountPreTax" and another for "amountNet".

Here is part of my html view:

<tr *ngFor="
let invoice of invoices |
invoicesFilter:term |
dateFrom: date1:whichDates |
dateTo: date2:whichDates">

inside this table i have iterated which displays data of each invoice.

Under that table I need to display sum of amountPreTax and amountNet so I could display it like

{{sumNet | number : '1.2-2'}} zł
{{sumPreTax | number : '1.2-2'}} zł