feat: currency formatter

Author: kvernon

README.md

@@ -89,9 +89,7 @@ Once a feature's PR is merged, the pipeline will run checks and publish.
 
 ## Missing features
 
-1. currency formatting
-2. easier setup
-3. apartments (passive investor)
+1. apartments (passive investor)
 
 ## Future
 

src/calculations/get-monthly-mortgage.ts

@@ -1,4 +1,5 @@
 import { differenceInMonths } from 'date-fns';
+import currency from '../formatters/currency';
 
 /**
  * formula for M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1].
@@ -20,7 +21,8 @@ export function getMonthlyMortgage(
   const i = loanRatePercent / 100 / 12;
   const n = loanTermInYears * 12;
 
-  return (p * i * Math.pow(1 + i, n)) / (Math.pow(1 + i, n) - 1);
+  const mort = (p * i * Math.pow(1 + i, n)) / (Math.pow(1 + i, n) - 1);
+  return currency(mort);
 }
 
 /**
@@ -29,7 +31,7 @@ export function getMonthlyMortgage(
  * @param cashDownPercent
  */
 export function getCashDown(purchasePrice: number, cashDownPercent: number) {
-  return (purchasePrice * cashDownPercent) / 100;
+  return currency((purchasePrice * cashDownPercent) / 100);
 }
 
 export function getSellPriceEstimate(
@@ -45,5 +47,5 @@ export function getSellPriceEstimate(
     result = result + (result * sellPriceAppreciationPercent) / 100;
   }
 
-  return result;
+  return currency(result);
 }

src/calculations/get-monthly-principal-interest-tax-interest.ts

@@ -1,4 +1,5 @@
 import { getMonthlyMortgage } from './get-monthly-mortgage';
+import currency from '../formatters/currency';
 
 /**
  * This gets you PITI!
@@ -28,5 +29,5 @@ export function getMonthlyPrincipalInterestTaxInterest(
     loanRatePercent,
     loanTermInYears
   );
-  return monthlyMortgage + annualTaxes / 12 + annualInsurance / 12;
+  return currency(monthlyMortgage + annualTaxes / 12 + annualInsurance / 12);
 }

src/formatters/currency.ts

@@ -0,0 +1,11 @@
+export default function (value: number /*?*/): number {
+  if (!value || value === 0) {
+    return 0;
+  }
+
+  const c = value
+    .toString()
+    .split('.')
+    .map((v, i) => (i % 2 !== 0 ? v.substr(0, 2) : v));
+  return parseFloat(c.join('.'));
+}

src/formatters/index.ts

@@ -0,0 +1 @@
+export * from './currency';

src/index.ts

@@ -1,6 +1,7 @@
 export * from './account';
 export * from './caching';
 export * from './calculations';
+export * from './formatters';
 export * from './generators';
 export * from './investments';
 export * from './ledger';

src/ledger/ledger-collection.ts

@@ -3,6 +3,7 @@ import itiriri, { IterableQuery } from 'itiriri';
 import { ILedgerSummary } from './i-ledger-summary';
 import { LedgerItemType } from './ledger-item-type';
 import { IRentalSavings, RentalSingleFamily } from '../properties';
+import currency from '../formatters/currency';
 
 export interface ILedgerCollection {
   getBalance(date: Date): number;
@@ -132,7 +133,9 @@ export class LedgerCollection implements ILedgerCollection {
 
     const salary = this.getSummaryByType(boundary, LedgerItemType.Salary);
     result.cashFlow = this.getSummaryByType(boundary, LedgerItemType.CashFlow);
-    result.averageCashFlow = boundary.filter((x) => x.type === LedgerItemType.CashFlow).average((x) => x.amount) || 0;
+    result.averageCashFlow = currency(
+      boundary.filter((x) => x.type === LedgerItemType.CashFlow).average((x) => x.amount) || 0
+    );
     result.equity = this.getSummaryByType(boundary, LedgerItemType.Equity);
     result.purchases = this.getSummaryByType(boundary, LedgerItemType.Purchase);
     result.balance = result.cashFlow + salary + result.equity - result.purchases || 0;
@@ -159,8 +162,8 @@ export class LedgerCollection implements ILedgerCollection {
       balance: summaries.sum((x) => x.balance || 0),
       equity: summaries.sum((x) => x.equity || 0),
       cashFlow: summaries.sum((x) => x.cashFlow || 0),
-      averageCashFlow: summaries.average((x) => x.cashFlow || 0),
-      purchases: summaries.average((x) => x.purchases || 0),
+      averageCashFlow: currency(summaries.average((x) => x.cashFlow || 0)),
+      purchases: summaries.sum((x) => x.purchases || 0),
     };
   }
 

src/properties/rental-single-family.ts

@@ -10,7 +10,7 @@ import { PurchaseRuleTypes } from '../rules/purchase-rule-types';
 import { canInvestByUser } from '../calculations/can-invest-by-user';
 import { IUserInvestorCheck } from '../account/i-user-investor-check';
 import { getCashDown, getSellPriceEstimate } from '../calculations/get-monthly-mortgage';
-import cloneDateUtc from '../utils/data-clone-date';
+import { cloneDateUtc } from '../utils/data-clone-date';
 import areSameDate from '../utils/data-are-same-date';
 import compareDates from '../utils/data-compare-date';
 
@@ -125,7 +125,7 @@ export class RentalSingleFamily implements IEntityExistence, IRentalSavings, IRe
       return undefined;
     }
 
-    return new Date(value.getUTCFullYear(), value.getUTCMonth(), 1);
+    return cloneDateUtc(value);
   }
 
   private _purchaseDate: Date | undefined;

src/time/movement.ts

@@ -7,7 +7,7 @@ import { IUser } from '../account/user';
 import { LedgerItemType } from '../ledger/ledger-item-type';
 import { LedgerItem } from '../ledger/ledger-item';
 import propertySort from '../properties/property-sort';
-import cloneDateUtc from '../utils/data-clone-date';
+import { cloneDateUtc } from '../utils/data-clone-date';
 
 export interface ILoopOptions {
   /**

src/time/simulate.ts

@@ -12,7 +12,7 @@ import { RentalSingleFamily } from '../properties';
 import { LedgerCollection, LedgerItem, LedgerItemType } from '../ledger';
 import { ValueCache } from '../caching/value-cache';
 import { loop } from './movement';
-import cloneDateUtc from '../utils/data-clone-date';
+import { cloneDateUtc } from '../utils/data-clone-date';
 
 export interface ISimulateOptions extends IPropertyEntityOptions {
   /**
@@ -67,12 +67,13 @@ export interface ISimulateOptions extends IPropertyEntityOptions {
  */
 export function simulate(options: ISimulateOptions): ITimeline {
   const formattedUtcDate = cloneDateUtc(options.startDate ?? new Date());
-  const valueCache = new ValueCache(cloneDateUtc(formattedUtcDate), [], options.maxRentalOpportunitiesSingleFamily);
+  const valueCache = new ValueCache(cloneDateUtc(formattedUtcDate), [], 2);
 
   const propertyGeneratorSingleFamily = Object.assign(
     new RentalGenerator<RentalSingleFamily>(valueCache, generateSingleFamily),
     options
   );
+  propertyGeneratorSingleFamily.maxRentalOpportunities = options.maxRentalOpportunitiesSingleFamily;
 
   const totalSavings = new LedgerItem();
   totalSavings.amount = options.amountInSavings;