Format currency

Format a numeric amount as currency for a given locale using Intl, honouring the currency's own minor-unit convention (USD→2, JPY→0). display selects the symbol, narrow symbol, ISO code or full name. An unknown currency or locale is a clean 400.

Round an amount to a currency's minor units (or an explicit minorUnits) with a chosen rounding mode: half-even (banker's, default), half-up, half-down, ceil, floor or trunc. Give a currency to derive minor units automatically (USD→2, JPY→0).

Split an amount into parts using integer minor-unit math so the shares always sum back to the exact original — no rounding drift. Pass parts for an even split, or ratios for a weighted one (e.g. [1,1,1] splits $100 into 33.34/33.33/33.33). The leftover minor units go to the largest fractional remainders.

Parse a formatted money string back into a number, using the locale's grouping and decimal separators (so '1.234,56' in de-DE → 1234.56). Currency symbols/codes and whitespace are stripped; parentheses or a leading minus mean negative. A string with no numeric amount is a clean 400.