taxes.js

/*

  # calculate your taxes in your browser console

  ## Usage ##

  taxes.bracket(0, 22000, .10)
  taxes.bracket(22001, 89450, .12);
  taxes.bracket(89451, 190750, .22);

  taxes.state(.05);

  taxes.income(100000);

  console.log("Total Taxes: ", taxes.calculate());
  console.log("Federal Taxes: ", taxes.calculateFederal());
  console.log("State Taxes: ", taxes.calculateState());
  console.log("Taxes Per Bracket: ", taxes.calculatePerBracket());

*/

// Define the taxes object
const taxes = {
  brackets: [],
  income: 0,
  stateTaxRate: 0,

  // Method to add a tax bracket
  bracket: function(min, max, rate) {
    this.brackets.push({ min, max, rate });
  },

  // Method to set the income
  income: function(amount) {
    this.income = amount;
  },

  // Method to set the state tax rate
  state: function(taxRate) {
    this.stateTaxRate = taxRate;
  },

  // Method to calculate state tax
  calculateState: function() {
    return this.income * this.stateTaxRate;
  },

  // Method to calculate federal tax
  calculateFederal: function() {
    let federalTax = 0;
    for (const bracket of this.brackets) {
      if (this.income > bracket.min) {
        const taxableIncome = Math.min(this.income, bracket.max) - bracket.min;
        federalTax += taxableIncome * bracket.rate;
      }
    }
    return federalTax;
  },

  // Method to calculate total expected taxes
  calculate: function() {
    const federalTax = this.calculateFederal();
    const stateTax = this.calculateState();
    return federalTax + stateTax;
  },

  // Method to calculate taxes per bracket including state tax
  calculatePerBracket: function() {
    let taxesPerBracket = [];
    for (const bracket of this.brackets) {
      if (this.income > bracket.min) {
        const taxableIncome = Math.min(this.income, bracket.max) - bracket.min;
        const tax = taxableIncome * bracket.rate;
        taxesPerBracket.push({
          range: `${bracket.min}-${bracket.max}`,
          rate: bracket.rate,
          tax: tax
        });
      }
    }
    // Add state tax as a separate bracket
    taxesPerBracket.push({
      range: `State Tax`,
      rate: this.stateTaxRate,
      tax: this.calculateState()
    });
    return taxesPerBracket;
  }
};

// Usage
taxes.bracket(0, 22000, .10)
taxes.bracket(22001, 89450, .12);
taxes.bracket(89451, 190750, .22);

taxes.state(.05);

taxes.income(100000);

console.log("Total Taxes: ", taxes.calculate());
console.log("Federal Taxes: ", taxes.calculateFederal());
console.log("State Taxes: ", taxes.calculateState());
console.log("Taxes Per Bracket: ", taxes.calculatePerBracket());