money cheatsheet

Every export of @deckyard/money. Guides are listed in the introduction.

jennifer

import "@deckyard/money/" as money;

Every failure is Error{kind: "money"}. A code is an ISO 4217 code such as "EUR"; a mode is one of MODES. Factors, rates and ratios are decimal strings such as "1.19".

Constants

Constant	Value	Meaning
`ERROR_KIND`	`"money"`	the `kind` of every error the deck throws
`MODES`	`["half-even", "half-up", "half-down", "up", "down", "ceiling", "floor"]`	the rounding modes
`MAX_TEXT`	`50`	the longest amount, factor, rate or ratio string
`MAX_PARTS`	`100000`	the most parts `allocate` and `allocateTo` make

Types

`Money`

Field	Meaning
`amount as int`	minor units: 1234 for 12.34 EUR
`currency as string`	the ISO 4217 code

Making and reading

Function	Returns	Does
`money.fromMinor(amount, code)`	`Money`	an amount of minor units
`money.zero(code)`	`Money`	zero
`money.parse(text, code)`	`Money`	read `"12.34"`; extra places only if zeros
`money.format(m)`	`string`	`"12.34"`, `"1200"` for JPY
`money.fromDecimal(d, code, mode)`	`Money`	a decimal in major units, rounded
`money.toDecimal(m)`	`decimal.Decimal`	the amount in major units

Currencies

Function	Returns	Does
`money.isCurrency(code)`	`bool`	whether the code is in the table
`money.digits(code)`	`int`	the minor units: 0, 2, 3 or 4
`money.currencies()`	`list of string`	every code, sorted
`money.published()`	`string`	the date of the ISO 4217 list used

Arithmetic

Function	Returns	Does
`money.add(a, b)`	`Money`	`a + b`
`money.subtract(a, b)`	`Money`	`a - b`
`money.sum(ms, code)`	`Money`	the total of a list; zero when empty
`money.negate(m)`	`Money`	`-m`
`money.absolute(m)`	`Money`	`\|m\|`
`money.multiply(m, factor, mode)`	`Money`	`m * factor`, rounded
`money.divide(m, divisor, mode)`	`Money`	`m / divisor`, rounded
`money.allocate(m, ratios)`	`list of Money`	split by ratios; the parts sum to `m`
`money.allocateTo(m, n)`	`list of Money`	split into `n` equal parts
`money.exchange(m, code, rate, mode)`	`Money`	into another currency at `rate`, rounded

Comparing

Function	Returns	Does
`money.compare(a, b)`	`int`	-1, 0 or 1
`money.lessThan(a, b)`	`bool`	`a < b`
`money.greaterThan(a, b)`	`bool`	`a > b`
`money.isZero(m)`	`bool`	`m == 0`
`money.isNegative(m)`	`bool`	`m < 0`
`money.isPositive(m)`	`bool`	`m > 0`

The currencies module

import "@deckyard/money/currencies.j" as currencies; reads the table itself. It is generated; see Currencies.

Constant	Value	Meaning
`currencies.PUBLISHED`	`"2026-09-17"`	the date of the ISO 4217 list
`currencies.DIGITS`	`{"AED": 2, ...}`	each code's minor units

#money cheatsheet

#Constants

#Types

#Money

#Making and reading

#Currencies

#Arithmetic

#Comparing

#The currencies module