442 lines
15 KiB
JavaScript
442 lines
15 KiB
JavaScript
import moment from 'moment';
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/***************************************************
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* HELPER: Approx State Tax Rates
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***************************************************/
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const APPROX_STATE_TAX_RATES = {
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AL: 0.05, AK: 0.00, AZ: 0.025, AR: 0.05, CA: 0.07, CO: 0.045, CT: 0.055, DE: 0.05,
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FL: 0.00, GA: 0.05, HI: 0.06, ID: 0.058, IL: 0.05, IN: 0.035, IA: 0.05, KS: 0.05,
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KY: 0.05, LA: 0.04, ME: 0.055, MD: 0.05, MA: 0.05, MI: 0.0425, MN: 0.06, MS: 0.04,
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MO: 0.05, MT: 0.05, NE: 0.05, NV: 0.00, NH: 0.00, NJ: 0.057, NM: 0.045, NY: 0.06,
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NC: 0.0475, ND: 0.02, OH: 0.04, OK: 0.045, OR: 0.07, PA: 0.03, RI: 0.045, SC: 0.04,
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SD: 0.00, TN: 0.00, TX: 0.00, UT: 0.045, VT: 0.055, VA: 0.05, WA: 0.00, WV: 0.05,
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WI: 0.05, WY: 0.00, DC: 0.05
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};
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/***************************************************
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* HELPER: Federal Tax Brackets
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***************************************************/
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const STANDARD_DEDUCTION_SINGLE = 13850;
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function calculateAnnualFederalTaxSingle(annualTaxable) {
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const brackets = [
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{ limit: 11000, rate: 0.10 },
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{ limit: 44725, rate: 0.12 },
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{ limit: 95375, rate: 0.22 },
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{ limit: 182100, rate: 0.24 },
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{ limit: 231250, rate: 0.32 },
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{ limit: 578125, rate: 0.35 },
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{ limit: Infinity, rate: 0.37 }
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];
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let tax = 0;
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let lastLimit = 0;
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for (let i = 0; i < brackets.length; i++) {
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const { limit, rate } = brackets[i];
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if (annualTaxable <= limit) {
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tax += (annualTaxable - lastLimit) * rate;
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break;
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} else {
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tax += (limit - lastLimit) * rate;
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lastLimit = limit;
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}
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}
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return tax;
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}
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/***************************************************
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* HELPER: Monthly Federal Tax (no YTD)
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* We just treat (monthlyGross * 12) - standardDed
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* -> bracket -> / 12
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***************************************************/
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function calculateMonthlyFedTaxNoYTD(monthlyGross) {
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const annualGross = monthlyGross * 12;
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let annualTaxable = annualGross - STANDARD_DEDUCTION_SINGLE;
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if (annualTaxable < 0) annualTaxable = 0;
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const annualTax = calculateAnnualFederalTaxSingle(annualTaxable);
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return annualTax / 12;
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}
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/***************************************************
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* HELPER: Monthly State Tax (no YTD)
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* Uses GA (5%) by default if user doesn't override
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***************************************************/
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function calculateMonthlyStateTaxNoYTD(monthlyGross, stateCode = 'GA') {
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const rate = APPROX_STATE_TAX_RATES[stateCode] ?? 0.05;
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return monthlyGross * rate;
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}
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/***************************************************
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* HELPER: Loan Payment (if not deferring)
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***************************************************/
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function calculateLoanPayment(principal, annualRate, years) {
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if (principal <= 0) return 0;
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const monthlyRate = annualRate / 100 / 12;
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const numPayments = years * 12;
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if (monthlyRate === 0) {
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return principal / numPayments;
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}
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return (
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(principal * monthlyRate) /
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(1 - Math.pow(1 + monthlyRate, -numPayments))
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);
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}
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/***************************************************
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* MAIN SIMULATION FUNCTION
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***************************************************/
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export function simulateFinancialProjection(userProfile) {
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/***************************************************
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* 1) DESTRUCTURE USER PROFILE
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***************************************************/
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const {
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// Basic incomes
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currentSalary = 0,
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monthlyExpenses = 0,
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monthlyDebtPayments = 0,
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partTimeIncome = 0,
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extraPayment = 0,
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// Student loan config
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studentLoanAmount = 0,
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interestRate = 5,
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loanTerm = 10,
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loanDeferralUntilGraduation = false,
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// College config
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inCollege = false,
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programType,
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hoursCompleted = 0,
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creditHoursPerYear,
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calculatedTuition,
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gradDate,
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startDate,
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academicCalendar = 'monthly',
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annualFinancialAid = 0,
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// Post-college salary
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expectedSalary = 0,
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// Savings & monthly contributions
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emergencySavings = 0,
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retirementSavings = 0,
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monthlyRetirementContribution = 0,
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monthlyEmergencyContribution = 0,
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// Surplus distribution
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surplusEmergencyAllocation = 50,
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surplusRetirementAllocation = 50,
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// Program length override
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programLength,
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// State code for taxes (default to GA if not provided)
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stateCode = 'GA',
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// Financial milestone impacts
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milestoneImpacts = []
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} = userProfile;
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/***************************************************
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* 2) CLAMP THE SCENARIO START TO MONTH-BEGIN
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***************************************************/
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const scenarioStartClamped = moment(startDate || new Date()).startOf('month');
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/***************************************************
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* 3) DETERMINE PROGRAM LENGTH (credit hours)
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***************************************************/
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let requiredCreditHours = 120;
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switch (programType) {
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case "Associate's Degree":
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requiredCreditHours = 60;
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break;
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case "Master's Degree":
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requiredCreditHours = 30;
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break;
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case "Doctoral Degree":
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requiredCreditHours = 60;
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break;
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// else Bachelor's = 120
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}
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const remainingCreditHours = Math.max(0, requiredCreditHours - hoursCompleted);
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const dynamicProgramLength = Math.ceil(
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remainingCreditHours / (creditHoursPerYear || 30)
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);
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const finalProgramLength = programLength || dynamicProgramLength;
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/***************************************************
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* 4) TUITION CALC: lumps, deferral, etc.
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***************************************************/
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const netAnnualTuition = Math.max(0, (calculatedTuition || 0) - (annualFinancialAid || 0));
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const totalTuitionCost = netAnnualTuition * finalProgramLength;
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let lumpsPerYear, lumpsSchedule;
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switch (academicCalendar) {
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case 'semester':
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lumpsPerYear = 2;
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lumpsSchedule = [0, 6];
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break;
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case 'quarter':
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lumpsPerYear = 4;
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lumpsSchedule = [0, 3, 6, 9];
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break;
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case 'trimester':
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lumpsPerYear = 3;
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lumpsSchedule = [0, 4, 8];
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break;
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case 'monthly':
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default:
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lumpsPerYear = 12;
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lumpsSchedule = [...Array(12).keys()];
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break;
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}
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const totalAcademicMonths = finalProgramLength * 12;
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const lumpAmount = totalTuitionCost / (lumpsPerYear * finalProgramLength);
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/***************************************************
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* 5) LOAN PAYMENT (if not deferring)
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***************************************************/
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let monthlyLoanPayment = loanDeferralUntilGraduation
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? 0
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: calculateLoanPayment(studentLoanAmount, interestRate, loanTerm);
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/***************************************************
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* 6) SETUP FOR THE SIMULATION LOOP
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***************************************************/
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const maxMonths = 240; // 20 years
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let loanBalance = Math.max(studentLoanAmount, 0);
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let loanPaidOffMonth = null;
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let currentEmergencySavings = emergencySavings;
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let currentRetirementSavings = retirementSavings;
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let projectionData = [];
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// Keep track of YTD gross & tax for reference
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let fedYTDgross = 0;
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let fedYTDtax = 0;
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let stateYTDgross = 0;
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let stateYTDtax = 0;
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let wasInDeferral = inCollege && loanDeferralUntilGraduation;
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const graduationDateObj = gradDate ? moment(gradDate).startOf('month') : null;
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console.log('simulateFinancialProjection - monthly tax approach');
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console.log('scenarioStartClamped:', scenarioStartClamped.format('YYYY-MM-DD'));
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/***************************************************
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* 7) THE MONTHLY LOOP
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***************************************************/
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for (let monthIndex = 0; monthIndex < maxMonths; monthIndex++) {
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// date for this iteration
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const currentSimDate = scenarioStartClamped.clone().add(monthIndex, 'months');
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// check if loan is fully paid
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if (loanBalance <= 0 && !loanPaidOffMonth) {
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loanPaidOffMonth = currentSimDate.format('YYYY-MM');
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}
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// Are we still in college?
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let stillInCollege = false;
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if (inCollege) {
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if (graduationDateObj) {
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stillInCollege = currentSimDate.isBefore(graduationDateObj, 'month');
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} else {
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stillInCollege = (monthIndex < totalAcademicMonths);
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}
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}
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/************************************************
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* 7.1 TUITION lumps
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************************************************/
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let tuitionCostThisMonth = 0;
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if (stillInCollege && lumpsPerYear > 0) {
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const academicYearIndex = Math.floor(monthIndex / 12);
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const monthInYear = monthIndex % 12;
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if (lumpsSchedule.includes(monthInYear) && academicYearIndex < finalProgramLength) {
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tuitionCostThisMonth = lumpAmount;
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}
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}
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// If deferring tuition => add to loan, no direct expense
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if (stillInCollege && loanDeferralUntilGraduation && tuitionCostThisMonth > 0) {
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loanBalance += tuitionCostThisMonth;
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tuitionCostThisMonth = 0;
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}
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/************************************************
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* 7.2 BASE MONTHLY INCOME
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************************************************/
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let baseMonthlyIncome = 0;
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if (!stillInCollege) {
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// user is out of college => expected or current
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baseMonthlyIncome = (expectedSalary || currentSalary) / 12;
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} else {
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// in college => might have partTimeIncome + current
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baseMonthlyIncome = (currentSalary / 12) + (partTimeIncome / 12);
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}
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/************************************************
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* 7.3 MILESTONE IMPACTS
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************************************************/
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let extraImpactsThisMonth = 0;
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milestoneImpacts.forEach((impact) => {
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const startDateClamped = moment(impact.start_date).startOf('month');
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let startOffset = startDateClamped.diff(scenarioStartClamped, 'months');
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if (startOffset < 0) startOffset = 0;
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let endOffset = Infinity;
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if (impact.end_date && impact.end_date.trim() !== '') {
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const endDateClamped = moment(impact.end_date).startOf('month');
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endOffset = endDateClamped.diff(scenarioStartClamped, 'months');
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if (endOffset < 0) endOffset = 0;
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}
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if (impact.impact_type === 'ONE_TIME') {
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if (monthIndex === startOffset) {
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if (impact.direction === 'add') {
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baseMonthlyIncome += impact.amount;
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} else {
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extraImpactsThisMonth += impact.amount;
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}
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}
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} else {
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// 'MONTHLY'
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if (monthIndex >= startOffset && monthIndex <= endOffset) {
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if (impact.direction === 'add') {
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baseMonthlyIncome += impact.amount;
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} else {
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extraImpactsThisMonth += impact.amount;
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}
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}
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}
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});
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/************************************************
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* 7.4 CALCULATE TAXES (No YTD approach)
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************************************************/
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const monthlyFederalTax = calculateMonthlyFedTaxNoYTD(baseMonthlyIncome);
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const monthlyStateTax = calculateMonthlyStateTaxNoYTD(baseMonthlyIncome, stateCode);
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const combinedTax = monthlyFederalTax + monthlyStateTax;
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// net after tax
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const netMonthlyIncome = baseMonthlyIncome - combinedTax;
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// increment YTD gross & tax for reference
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fedYTDgross += baseMonthlyIncome;
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fedYTDtax += monthlyFederalTax;
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stateYTDgross += baseMonthlyIncome;
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stateYTDtax += monthlyStateTax;
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/************************************************
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* 7.5 LOAN + EXPENSES
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************************************************/
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const nowExitingCollege = wasInDeferral && !stillInCollege;
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if (nowExitingCollege) {
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monthlyLoanPayment = calculateLoanPayment(loanBalance, interestRate, loanTerm);
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}
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let totalMonthlyExpenses = monthlyExpenses + monthlyDebtPayments + tuitionCostThisMonth + extraImpactsThisMonth;
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if (stillInCollege && loanDeferralUntilGraduation) {
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// accumulate interest
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const interestForMonth = loanBalance * (interestRate / 100 / 12);
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loanBalance += interestForMonth;
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} else {
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// pay principal
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if (loanBalance > 0) {
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const interestForMonth = loanBalance * (interestRate / 100 / 12);
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const principalForMonth = Math.min(
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loanBalance,
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(monthlyLoanPayment + extraPayment) - interestForMonth
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);
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loanBalance = Math.max(loanBalance - principalForMonth, 0);
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totalMonthlyExpenses += (monthlyLoanPayment + extraPayment);
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}
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}
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let leftover = netMonthlyIncome - totalMonthlyExpenses;
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// baseline contributions
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const baselineContributions = monthlyRetirementContribution + monthlyEmergencyContribution;
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let effectiveRetirementContribution = 0;
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let effectiveEmergencyContribution = 0;
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if (leftover >= baselineContributions) {
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effectiveRetirementContribution = monthlyRetirementContribution;
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effectiveEmergencyContribution = monthlyEmergencyContribution;
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leftover -= baselineContributions;
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}
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const actualExpensesPaid = totalMonthlyExpenses + effectiveRetirementContribution + effectiveEmergencyContribution;
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let shortfall = actualExpensesPaid - netMonthlyIncome;
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// cover shortfall with emergency
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if (shortfall > 0) {
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const canCover = Math.min(shortfall, currentEmergencySavings);
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currentEmergencySavings -= canCover;
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shortfall -= canCover;
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// leftover -= shortfall; // if you want negative leftover
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}
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// Surplus => leftover
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if (leftover > 0) {
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const totalPct = surplusEmergencyAllocation + surplusRetirementAllocation;
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const emergPortion = leftover * (surplusEmergencyAllocation / totalPct);
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const retPortion = leftover * (surplusRetirementAllocation / totalPct);
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currentEmergencySavings += emergPortion;
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currentRetirementSavings += retPortion;
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}
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// net savings
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const netSavings = netMonthlyIncome - actualExpensesPaid;
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projectionData.push({
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month: currentSimDate.format('YYYY-MM'),
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grossMonthlyIncome: +baseMonthlyIncome.toFixed(2),
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monthlyFederalTax: +monthlyFederalTax.toFixed(2),
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monthlyStateTax: +monthlyStateTax.toFixed(2),
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combinedTax: +combinedTax.toFixed(2),
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netMonthlyIncome: +netMonthlyIncome.toFixed(2),
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totalExpenses: +actualExpensesPaid.toFixed(2),
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effectiveRetirementContribution: +effectiveRetirementContribution.toFixed(2),
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effectiveEmergencyContribution: +effectiveEmergencyContribution.toFixed(2),
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netSavings: +netSavings.toFixed(2),
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emergencySavings: +currentEmergencySavings.toFixed(2),
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retirementSavings: +currentRetirementSavings.toFixed(2),
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loanBalance: +loanBalance.toFixed(2),
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// actual loan payment
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loanPaymentThisMonth: +(monthlyLoanPayment + extraPayment).toFixed(2),
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// YTD references
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fedYTDgross: +fedYTDgross.toFixed(2),
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fedYTDtax: +fedYTDtax.toFixed(2),
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stateYTDgross: +stateYTDgross.toFixed(2),
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stateYTDtax: +stateYTDtax.toFixed(2),
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});
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// update deferral
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wasInDeferral = stillInCollege && loanDeferralUntilGraduation;
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}
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return {
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projectionData,
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loanPaidOffMonth,
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finalEmergencySavings: +currentEmergencySavings.toFixed(2),
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finalRetirementSavings: +currentRetirementSavings.toFixed(2),
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finalLoanBalance: +loanBalance.toFixed(2),
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// Final YTD totals
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fedYTDgross: +fedYTDgross.toFixed(2),
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fedYTDtax: +fedYTDtax.toFixed(2),
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stateYTDgross: +stateYTDgross.toFixed(2),
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stateYTDtax: +stateYTDtax.toFixed(2),
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};
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}
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