Function significantDigits

test/big-decimal/cross-validation.test.ts:20–38

* Extract significant digits from a numeric string. * Strips sign, decimal point, leading zeros, and trailing zeros. * Returns only the significant digit sequence.

(s: string)

 * Returns only the significant digit sequence.
 */
function significantDigits(s: string): string {
  // Remove sign
  if (s.startsWith('-') || s.startsWith('+')) s = s.slice(1);

  // Handle scientific notation: normalize to plain digits
  const eIdx = s.search(/[eE]/);
  if (eIdx !== -1) {
    // Extract mantissa digits (ignore exponent for digit comparison)
    s = s.slice(0, eIdx);
  }

  // Remove decimal point
  s = s.replace('.', '');

  // Remove leading zeros
  s = s.replace(/^0+/, '');

  return s;
}

/**
 * Compare the first `matchDigits` significant digits of two numeric strings.