How to Build a How Much Calculator

function calculateHowMuch(inputs) {
  // Validate inputs
  if (!validateInputs(inputs)) {
    return { error: 'Invalid inputs provided' };
  }

  // Apply the how much formula
  const result = applyFormula(inputs);

  // Return result with breakdown
  return {
    result,
    breakdown: generateBreakdown(inputs, result),
    formula: getFormulaExplanation()
  };
}

function validateInputs(inputs) {
  // Add validation logic specific to how much
  return Object.values(inputs).every(v => v !== null && !isNaN(v));
}