src/fed2019/Form1098.ts

   1 // Copyright 2021 Blue Static <https://www.bluestatic.org>
   2 // This program is free software licensed under the GNU General Public License,
   3 // version 3.0. The full text of the license can be found in LICENSE.txt.
   4 // SPDX-License-Identifier: GPL-3.0-only
   5
   6 import { TaxReturn, Form, Person } from '../core';
   7 import { InputLine, ComputedLine, FormatType, sumFormLines, sumLineOfForms } from '../core/Line';
   8
   9 import Form1040, { FilingStatus } from './Form1040';
  10
  11 export interface Form1098Input {
  12   recipient: string;
  13   payee: Person;
  14   mortgageInterestReceived: number;
  15   // This is used for computing the "average mortgage balance." Consult Pub 936 and enter
  16   // a different value than the one on Form 1098 to use that instead for the average
  17   // balance calculations.
  18   outstandingMortgagePrincipal: number;
  19   mortgageOriginationDate: Date;
  20   refundOfOverpaidInterest?: number;
  21   mortgageInsurancePremiums?: number;
  22   pointsPaidOnPurchaseOfPrincipalResidence?: number;
  23 };
  24
  25 class Input<T extends keyof Form1098Input> extends InputLine<Form1098Input, T> {};
  26
  27 export class Form1098 extends Form<Form1098Input> {
  28   readonly name = '1098';
  29
  30   readonly supportsMultipleCopies = true;
  31
  32   readonly includeJointPersonForms = true;
  33
  34   person() { return this.getInput('payee'); }
  35
  36   readonly lines = {
  37     'recipient': new Input('recipient'),
  38     'payee': new Input('payee'),
  39     '1': new Input('mortgageInterestReceived'),
  40     '2': new Input('outstandingMortgagePrincipal'),
  41     '3': new Input('mortgageOriginationDate'),
  42     '4': new Input('refundOfOverpaidInterest'),
  43     '5': new Input('mortgageInsurancePremiums'),
  44     '6': new Input('pointsPaidOnPurchaseOfPrincipalResidence'),
  45   };
  46 };
  47
  48 const kGrandfatheredDate = new Date('1987-10-13');
  49 const kLimitationStartDate = new Date('2017-12-15');
  50
  51 // Pub. 936 Worksheet
  52 export class MortgageInterestDeductionWorksheet extends Form {
  53   readonly name = 'Mortgage Interest Deduction Worksheet';
  54
  55   private get1098sMatchingPredicate(tr: TaxReturn, pred: (Form1098) => boolean): Form1098[] {
  56     return tr.findForms(Form1098).filter(pred);
  57   }
  58
  59   deductibleMortgateInterest(tr: TaxReturn): number {
  60     const l11 = this.getValue(tr, '11');
  61     const l12 = this.getValue(tr, '12');
  62     if (l11 < l12) {
  63       return this.getValue(tr, '15');
  64     }
  65     return sumLineOfForms(tr, tr.findForms(Form1098), '1');
  66   }
  67
  68   readonly lines = {
  69     '1': new ComputedLine((tr): number => {
  70       const f1098s = this.get1098sMatchingPredicate(tr, f => f.getValue(tr, '3') <= kGrandfatheredDate);
  71       if (f1098s.length == 0)
  72         return 0;
  73       return sumLineOfForms(tr, f1098s, '2') / f1098s.length;
  74     }, 'Average balance of grandfathered debt'),
  75     '2': new ComputedLine((tr): number => {
  76       const f1098s = this.get1098sMatchingPredicate(tr, f => {
  77         const date = f.getValue(tr, '3');
  78         return date >= kGrandfatheredDate && date <= kLimitationStartDate;
  79       });
  80       if (f1098s.length == 0)
  81         return 0;
  82       return sumLineOfForms(tr, f1098s, '2') / f1098s.length;
  83     }, 'Average balance of pre-limitation debt'),
  84     '3': new ComputedLine((tr): number => {
  85       if (tr.getForm(Form1040).filingStatus == FilingStatus.MarriedFilingSeparate)
  86         return 500_000;
  87       return 1_000_000;
  88     }),
  89     '4': new ComputedLine((tr): number => Math.max(this.getValue(tr, '1'), this.getValue(tr, '3'))),
  90     '5': new ComputedLine((tr): number => sumFormLines(tr, this, ['1', '2'])),
  91     '6': new ComputedLine((tr): number => Math.min(this.getValue(tr, '4'), this.getValue(tr, '5'))),
  92     '7': new ComputedLine((tr): number => {
  93       const f1098s = this.get1098sMatchingPredicate(tr, f => f.getValue(tr, '3') > kLimitationStartDate);
  94       if (f1098s.length == 0)
  95         return 0;
  96       return sumLineOfForms(tr, f1098s, '2') / f1098s.length;
  97     }, 'Average balance of post-limitation debt'),
  98     '8': new ComputedLine((tr): number => {
  99       const fs = tr.getForm(Form1040).filingStatus;
 100       return tr.constants.mortgatgeInterestDeduction.limit[fs];
 101     }),
 102     '9': new ComputedLine((tr): number => Math.max(this.getValue(tr, '6'), this.getValue(tr, '8'))),
 103     '10': new ComputedLine((tr): number => sumFormLines(tr, this, ['6', '7'])),
 104     '11': new ComputedLine((tr): number => Math.min(this.getValue(tr, '9'), this.getValue(tr, '10')), 'Qualified loan limit'),
 105
 106     '12': new ComputedLine((tr): number => sumFormLines(tr, this, ['1', '2', '7']), 'Total of all average balanaces'),
 107     '13': new ComputedLine((tr): number => sumLineOfForms(tr, tr.findForms(Form1098), '1'), 'Total interest paid'),
 108     '14': new ComputedLine((tr): number => this.getValue(tr, '11') / this.getValue(tr, '12'), undefined, { formatType: FormatType.Decimal }),
 109     '15': new ComputedLine((tr): number => this.getValue(tr, '13') * this.getValue(tr, '14'), 'Deductible home mortgage interest'),
 110     '16': new ComputedLine((tr): number => this.getValue(tr, '13') - this.getValue(tr, '15'), 'Non-deductible interest'),
 111   };
 112 };