export function isNumber(val: unknown) {
  return !isNaN(parseInt(String(val)));
}

export class DecimalPrecision {
  // Decimal round (half away from zero)
  static round(num: number, decimalPlaces: number) {
    const p = Math.pow(10, decimalPlaces || 0);
    const n = num * p * (1 + Number.EPSILON);
    return Math.round(n) / p;
  }
  // Decimal ceil
  static ceil(num: number, decimalPlaces: number) {
    const p = Math.pow(10, decimalPlaces || 0);
    const n = num * p * (1 - Math.sign(num) * Number.EPSILON);
    return Math.ceil(n) / p;
  }
  // Decimal floor
  static floor(num: number, decimalPlaces: number) {
    const p = Math.pow(10, decimalPlaces || 0);
    const n = num * p * (1 + Math.sign(num) * Number.EPSILON);
    return Math.floor(n) / p;
  }
  // Decimal trunc
  static trunc(num: number, decimalPlaces: number) {
    return (num < 0 ? DecimalPrecision.ceil : DecimalPrecision.floor)(
      num,
      decimalPlaces
    );
  }
  // Format using fixed-point notation
  static toFixed(num: number, decimalPlaces: number) {
    return DecimalPrecision.round(num, decimalPlaces).toFixed(decimalPlaces);
  }
  // Count decimals
  static countDecimals(num: number) {
    const s = num.toExponential();
    const [before, after] = s.split("e");
    const exp = parseInt(after);
    const dec = before.split(".")[1];
    const count = (dec || "").length - exp;
    return Math.max(0, count);
  }
}