50 lines
1.2 KiB
TypeScript
50 lines
1.2 KiB
TypeScript
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import { Injectable } from '@angular/core';
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import Big from 'big.js';
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@Injectable()
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export class FireCalculatorService {
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private readonly COMPOUND_PERIOD = 12;
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private readonly CONTRIBUTION_PERIOD = 12;
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/**
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* @constructor
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*/
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public constructor() {}
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public calculateCompoundInterest({
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P,
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period,
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PMT,
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r
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}: {
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P: number;
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period: number;
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PMT: number;
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r: number;
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}) {
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let interest = new Big(0);
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const principal = new Big(P).plus(
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new Big(PMT).mul(this.CONTRIBUTION_PERIOD).mul(period)
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);
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let totalAmount = principal;
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if (r) {
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const compoundInterestForPrincipal = new Big(1)
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.plus(new Big(r).div(this.COMPOUND_PERIOD))
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.pow(new Big(this.COMPOUND_PERIOD).mul(period).toNumber());
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const compoundInterest = new Big(P).mul(compoundInterestForPrincipal);
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const contributionInterest = new Big(
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new Big(PMT).mul(compoundInterestForPrincipal.minus(1))
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).div(new Big(r).div(this.CONTRIBUTION_PERIOD));
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interest = compoundInterest.plus(contributionInterest).minus(principal);
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totalAmount = compoundInterest.plus(contributionInterest);
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}
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return {
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interest,
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principal,
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totalAmount
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};
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}
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}
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