Rounding, precision, and signs

Use the fixed-decimal preset for ordinary numeric display. Use Intl.NumberFormat in a Core template when a report needs a specific rounding or sign policy. These options change display, not arithmetic or stored values.

Cash-style increments

This example rounds the display to the nearest 0.05 major unit. Currency selection alone does not enable cash rounding:

const cash = new Intl.NumberFormat('de-CH', {
  style: 'currency', currency: 'CHF',
  minimumFractionDigits: 2, maximumFractionDigits: 2,
  roundingIncrement: 5, roundingMode: 'halfExpand',
});
grid.columns = [{
  prop: 'amount', name: 'Cash display (CHF)', readonly: true,
  cellTemplate: (_h, { value }) => value == null ? '' : cash.format(value),
}];
grid.source = [{ amount: 1.02 }, { amount: 1.03 }];

These display with amounts 1.00 and 1.05; currency placement follows the locale. The source still contains 1.02 and 1.03. This illustrates an increment, not a jurisdiction’s payment or accounting rule. Put actual business rounding in your calculation layer.

Check support in the browsers you ship. Some engines silently ignore newer options. For this recipe, cash.resolvedOptions().roundingIncrement === 5 confirms the increment was recognized; do not silently substitute a different rounding policy.

Signs for deltas

Construct a formatter with { signDisplay: 'exceptZero', minimumFractionDigits: 1, maximumFractionDigits: 1 } and use the same template pattern. In en-US, 5 displays as +5.0, -5 as -5.0, and 0 as 0.0. This is useful for BI period changes. For ratio changes, also set style: 'percent' and store fractions.

Intl option families

These are Intl options, not fields on dataGridFormat.value:

Need	Options and decisions
Required leading digits	minimumIntegerDigits; identifiers should usually remain text
Fixed or optional decimal places	minimumFractionDigits, maximumFractionDigits
Scientific precision	minimumSignificantDigits, maximumSignificantDigits
Combining significant and fraction limits	roundingPriority: auto, morePrecision, lessPrecision; choose deliberately
Rounding direction/ties	roundingMode: ceil, floor, expand, trunc, halfCeil, halfFloor, halfExpand, halfTrunc, halfEven
Rounding to an increment	roundingIncrement; fraction bounds must agree; cannot combine freely with significant-digit rounding
Suppress decimals for whole results	trailingZeroDisplay: 'stripIfInteger'
Plus/minus policy	signDisplay: auto, never, always, exceptZero, negative; consider negative zero
Group separators	useGrouping; available policies depend on runtime and notation
Currency representation	currencyDisplay: symbol, narrowSymbol, code, name; currencySign: standard, accounting
Magnitude and labels	notation, compactDisplay, style, unit, unitDisplay
Locale negotiation and digits	localeMatcher, numberingSystem, or locale Unicode extensions

Specifying only one fraction bound can interact with a default for the other bound. Inspect resolvedOptions() when precision surprises you. For half-even rounding, set roundingMode: 'halfEven' with the desired precision; do not assume a binary floating-point input exactly represents a decimal tie.

See scientific notation and units for template setup, countries and locales for digits, and the ECMA-402 NumberFormat specification for allowed option combinations and runtime behavior.