Replace Nested Conditional with Guard Clauses

Goal

Edge cases bail out early at the top of the function; the main flow is unindented and tells the happy path linearly.

Before the refactoring

function payAmount(employee) {
  if (employee.isSeparated) {
    return separationPay(employee);
  } else {
    if (employee.isRetired) {
      return retirementPay(employee);
    } else {
      return regularPay(employee);
    }
  }
}

After the refactoring

function payAmount(employee) {
  if (employee.isSeparated) return separationPay(employee);
  if (employee.isRetired)   return retirementPay(employee);
  return regularPay(employee);
}

Savings

Indentation drops; the dominant case is obvious; new edge cases land at the top without disturbing the rest.

Note

If multiple paths share work, premature returns can duplicate that work — extract first, then guard.