Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Calculate tax burden of IL joint filers in JS under the Fair Tax Amendment
// gonna refer to this as bracket0, bracket1 etc
//| Income | Marginal Tax Rate |
//|------------------------|-------------------|
//| $0 – $10,000 | 4.75% |
//| $10,001 – $100,000 | 4.90% |
//| $100,001 – $250,000 | 4.95% |
//| $250,001 – $500,000 | 7.75% |
//| $500,001 – $1,000,000 | 7.85% |
//| $1,000,001 and above | 7.95% on net |
const brackets = [
{ min: 0, max: 10000, rate: 0.0475 },
{ min: 10001, max: 100000, rate: 0.049 },
{ min: 100001, max: 250000, rate: 0.0495 },
{ min: 250001, max: 500000, rate: 0.0775 },
{ min: 500001, max: 1000000, rate: 0.0785 },
];
// assume income is Number
function calculateNetTaxForILJointFiler(income) {
const truncatedIncome = Math.floor(income); // taxes are always calculated with income truncated
let rtn = 0;
if (truncatedIncome >= 1000001) rtn = truncatedIncome * 0.0795; // sighs non marginal
// this is not performant in any way but that's OK
for (const bracket of brackets) {
const func = getBracketFunction(bracket.min, bracket.max, bracket.rate);
const bracketRtn = func(truncatedIncome);
rtn += bracketRtn.amount;
if (bracketRtn.done) break;
}
return Math.floor(rtn);
}
const getBracketFunction = (min, max, rate) => {
return (income) => {
if (income < min) return { amount: 0, done: true };
if (income > max) return { amount: rate * (max - min), done: false };
// in between
return { amount: rate * (income - min), done: true };
};
};
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment