Function withPrecision

test/big-decimal/cross-validation.test.ts:96–107

* Save and restore precision for both libraries.

(prec: number, fn: () => T)

 * Save and restore precision for both libraries.
 */
function withPrecision<T>(prec: number, fn: () => T): T {
  const savedBD = BigDecimal.precision;
  const savedDJ = Decimal.precision;
  try {
    BigDecimal.precision = prec;
    Decimal.set({ precision: prec });
    return fn();
  } finally {
    BigDecimal.precision = savedBD;
    Decimal.set({ precision: savedDJ });
  }
}

// ================================================================
// Division