calc.ts

export function abbrieviate(value: number): string {
  const suffixes = ['', 'K', 'M', 'B'];
  const suffixNum = Math.min(Math.floor(('' + value).length / 3), 3);
  const shortValue = parseFloat(
    (suffixNum !== 0 ? value / Math.pow(1000, suffixNum) : value).toFixed(2),
  );
  return shortValue + suffixes[suffixNum];
}

export function round(value: number, precision: number): number {
  const shift = Math.pow(10, precision);
  return Math.round(value * shift) / shift;
}

export function sigfig(value: number, precision: number): number {
  const radix = Math.floor(value);
  const remainder = value % 1;
  if (radix > 0) {
    return round(value, Math.max(precision - radix.toString().length));
  } else {
    const firstSigFig = remainder
      .toString()
      .replace(/^0./, '')
      .match(/[1-9]/i);
    if (firstSigFig == null) {
      return value;
    }
    const idx = firstSigFig.index as number;
    return round(value, idx + precision);
  }
}

export function formatPrice(price: number): string {
  const radix = Math.floor(price);
  const digitNum = radix.toString().length;
  if (digitNum > 3) {
    return radix.toLocaleString();
  } else if (digitNum <= 3 && radix !== 0) {
    return round(price, 2).toString();
  } else {
    return sigfig(price, 3).toString();
  }
}