// This approach calculates taxes based on the selected filing status from the URL. // It handles NaN cases, shows a column for the amount paid in taxes, and // provides links to switch between different filing statuses. // The code parses CSV data, stores it in a structured format, and provides // an interface for viewing tax calculations without using blob storage. const csvData = ` year,incomeTaxRate,incomeGreaterThan,incomeNotGreaterThan,filingStatus 2019,0.1,0,9700,single 2019,0.12,9701,39475,single 2019,0.22,39476,84200,single 2019,0.24,84201,160725,single 2019,0.32,160726,204100,single 2019,0.35,204101,510300,single 2019,0.37,510301,,single 2019,0.1,0,19400,marriedFilingJointly 2019,0.12,19401,78950,marriedFilingJointly 2019,0.22,78951,168400,marriedFilingJointly 2019,0.24,168401,321450,marriedFilingJointly 2019,0.32,321451,408200,marriedFilingJointly 2019,0.35,408201,612350,marriedFilingJointly 2019,0.37,612351,,marriedFilingJointly 2019,0.1,0,13850,headOfHousehold 2019,0.12,13851,52850,headOfHousehold 2019,0.22,52851,84200,headOfHousehold 2019,0.24,84201,160700,headOfHousehold 2019,0.32,160701,204100,headOfHousehold 2019,0.35,204101,510300,headOfHousehold 2019,0.37,510301,,headOfHousehold 2019,0.1,0,9700,marriedFilingSeparately 2019,0.12,9701,39475,marriedFilingSeparately 2019,0.22,39476,84200,marriedFilingSeparately 2019,0.24,84201,160725,marriedFilingSeparately 2019,0.32,160726,204100,marriedFilingSeparately 2019,0.35,204101,306175,marriedFilingSeparately 2019,0.37,306176,,marriedFilingSeparately `; interface TaxBracket { rate: number; min: number; max: number; filingStatus: string; } function parseCsv(csv: string): TaxBracket[] { const lines = csv.trim().split("\n"); const headers = lines.shift()?.split(","); return lines.map(line => { const [_, rate, min, max, filingStatus] = line.split(","); return { rate: parseFloat(rate), min: parseInt(min), max: max ? parseInt(max) : Infinity, filingStatus, }; }); } function calculateTax( income: number, filingStatus: string, taxBrackets: TaxBracket[] ): number { if (isNaN(income) || income <= 0) return 0; let tax = 0; const relevantBrackets = taxBrackets.filter( (bracket) => bracket.filingStatus === filingStatus ); for (const bracket of relevantBrackets) { if (income > bracket.min) { // Calculate the taxable income within this bracket const taxableIncome = Math.min(income, bracket.max) - bracket.min; // Add tax for this bracket tax += taxableIncome * bracket.rate; } } return tax; } const statusMap = { single: "Single", marriedFilingJointly: "Married (Filing Jointly)", marriedFilingSeparately: "Married (Filing Separately)", headOfHousehold: "Head of Household", }; function generateHtml(taxBrackets: TaxBracket[], selectedFilingStatus: string): string { let tableRows = ""; for (let income = 0; income <= 1000000; income += 1000) { const tax = calculateTax(income, selectedFilingStatus, taxBrackets); const effectiveRate = tax / income * 100; const effectiveRateStr = isNaN(effectiveRate) ? 0 : effectiveRate.toFixed(2); tableRows += `$${income.toLocaleString()}${effectiveRateStr}%${ tax.toLocaleString("en-US", { style: "currency", currency: "USD" }) }`; } const statusLinks = Object.entries(statusMap) .map( ([status, label]) => `${label}` ) .join(" | "); return ` US Federal Income Tax Rates 2019

How much federal tax does every income level pay?

Many people don't understand how graduated income tax rates work. Don't worry about the brackets, here's the percentage you'll actually pay at every income level.

Based on the 2019 US federal tax brackets.

Not a real tax calculator! Use IRS Free File for that.

Fork the code here →

Filing Status
${statusLinks}

${tableRows}

Taxable Yearly Income	Effective Tax Rate	Yearly Federal Tax

`; } export default async function main(req: Request): Promise { const taxBrackets = parseCsv(csvData); const url = new URL(req.url); const selectedFilingStatus = url.pathname.slice(1) || "single"; if ( !["headOfHousehold", "marriedFilingJointly", "single", "marriedFilingSeparately"].includes(selectedFilingStatus) ) { return new Response("Invalid filing status", { status: 400 }); } const html = generateHtml(taxBrackets, selectedFilingStatus); return new Response(html, { headers: { "Content-Type": "text/html" }, }); }

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