Function formatNumber

src/components/formatTooltip.ts:16–26

(value: number)

}

function formatNumber(value: number): string {
  if (!Number.isFinite(value)) return EM_DASH;

  // Normalize -0 to 0 for display stability.
  const normalized = Object.is(value, -0) ? 0 : value;

  // Maximum 2 decimal places, trim trailing zeros.
  const fixed = normalized.toFixed(2);
  const trimmed = fixed.replace(/\.?0+$/, '');
  return trimmed === '-0' ? '0' : trimmed;
}

function resolveSeriesName(params: TooltipParams): string {
  const trimmed = params.seriesName.trim();