Function parseNanos

packages/effect/src/Duration.ts:43–56

(input: string, scale: bigint)

const roundMillisToNanos = (millis: number): bigint => roundTiesAwayFromZero(millis * 1_000_000)

const parseNanos = (input: string, scale: bigint): bigint => {
  const decimalIndex = input.indexOf(".")
  if (decimalIndex === -1) return BigInt(input) * scale

  const isNegative = input[0] === "-"
  const fractional = input.slice(decimalIndex + 1)
  const fractionalScale = bigint10 ** BigInt(fractional.length)
  const scaled = (
    BigInt(input.slice(isNegative ? 1 : 0, decimalIndex)) * fractionalScale + BigInt(fractional)
  ) * scale
  const rounded = scaled / fractionalScale +
    (scaled % fractionalScale * bigint2 >= fractionalScale ? bigint1 : bigint0)
  return isNegative ? -rounded : rounded
}

const nanosToHrTime = (nanos: bigint): [seconds: number, nanos: number] => {
  const sign = nanos < bigint0 ? -bigint1 : bigint1